-/* -----------------------------------------------------------------------------
- * $Id: Schedule.c,v 1.22 1999/06/25 09:17:58 simonmar Exp $
+/* ---------------------------------------------------------------------------
+ * $Id: Schedule.c,v 1.76 2000/08/15 14:18:43 simonmar Exp $
*
- * (c) The GHC Team, 1998-1999
+ * (c) The GHC Team, 1998-2000
*
* Scheduler
*
- * ---------------------------------------------------------------------------*/
+ * The main scheduling code in GranSim is quite different from that in std
+ * (concurrent) Haskell: while concurrent Haskell just iterates over the
+ * threads in the runnable queue, GranSim is event driven, i.e. it iterates
+ * over the events in the global event queue. -- HWL
+ * --------------------------------------------------------------------------*/
+
+//@node Main scheduling code, , ,
+//@section Main scheduling code
+
+/* Version with scheduler monitor support for SMPs.
+
+ This design provides a high-level API to create and schedule threads etc.
+ as documented in the SMP design document.
+
+ It uses a monitor design controlled by a single mutex to exercise control
+ over accesses to shared data structures, and builds on the Posix threads
+ library.
+
+ The majority of state is shared. In order to keep essential per-task state,
+ there is a Capability structure, which contains all the information
+ needed to run a thread: its STG registers, a pointer to its TSO, a
+ nursery etc. During STG execution, a pointer to the capability is
+ kept in a register (BaseReg).
+
+ In a non-SMP build, there is one global capability, namely MainRegTable.
+
+ SDM & KH, 10/99
+*/
+
+//@menu
+//* Includes::
+//* Variables and Data structures::
+//* Main scheduling loop::
+//* Suspend and Resume::
+//* Run queue code::
+//* Garbage Collextion Routines::
+//* Blocking Queue Routines::
+//* Exception Handling Routines::
+//* Debugging Routines::
+//* Index::
+//@end menu
+
+//@node Includes, Variables and Data structures, Main scheduling code, Main scheduling code
+//@subsection Includes
#include "Rts.h"
#include "SchedAPI.h"
#include "StgMiscClosures.h"
#include "Storage.h"
#include "Evaluator.h"
+#include "Exception.h"
#include "Printer.h"
#include "Main.h"
#include "Signals.h"
-#include "Profiling.h"
#include "Sanity.h"
+#include "Stats.h"
+#include "Itimer.h"
+#include "Prelude.h"
+#if defined(GRAN) || defined(PAR)
+# include "GranSimRts.h"
+# include "GranSim.h"
+# include "ParallelRts.h"
+# include "Parallel.h"
+# include "ParallelDebug.h"
+# include "FetchMe.h"
+# include "HLC.h"
+#endif
+#include "Sparks.h"
+
+#include <stdarg.h>
+
+//@node Variables and Data structures, Prototypes, Includes, Main scheduling code
+//@subsection Variables and Data structures
+
+/* Main threads:
+ *
+ * These are the threads which clients have requested that we run.
+ *
+ * In an SMP build, we might have several concurrent clients all
+ * waiting for results, and each one will wait on a condition variable
+ * until the result is available.
+ *
+ * In non-SMP, clients are strictly nested: the first client calls
+ * into the RTS, which might call out again to C with a _ccall_GC, and
+ * eventually re-enter the RTS.
+ *
+ * Main threads information is kept in a linked list:
+ */
+//@cindex StgMainThread
+typedef struct StgMainThread_ {
+ StgTSO * tso;
+ SchedulerStatus stat;
+ StgClosure ** ret;
+#ifdef SMP
+ pthread_cond_t wakeup;
+#endif
+ struct StgMainThread_ *link;
+} StgMainThread;
+
+/* Main thread queue.
+ * Locks required: sched_mutex.
+ */
+static StgMainThread *main_threads;
+
+/* Thread queues.
+ * Locks required: sched_mutex.
+ */
+#if defined(GRAN)
+
+StgTSO* ActiveTSO = NULL; /* for assigning system costs; GranSim-Light only */
+/* rtsTime TimeOfNextEvent, EndOfTimeSlice; now in GranSim.c */
+
+/*
+ In GranSim we have a runable and a blocked queue for each processor.
+ In order to minimise code changes new arrays run_queue_hds/tls
+ are created. run_queue_hd is then a short cut (macro) for
+ run_queue_hds[CurrentProc] (see GranSim.h).
+ -- HWL
+*/
+StgTSO *run_queue_hds[MAX_PROC], *run_queue_tls[MAX_PROC];
+StgTSO *blocked_queue_hds[MAX_PROC], *blocked_queue_tls[MAX_PROC];
+StgTSO *ccalling_threadss[MAX_PROC];
+/* We use the same global list of threads (all_threads) in GranSim as in
+ the std RTS (i.e. we are cheating). However, we don't use this list in
+ the GranSim specific code at the moment (so we are only potentially
+ cheating). */
+
+#else /* !GRAN */
StgTSO *run_queue_hd, *run_queue_tl;
StgTSO *blocked_queue_hd, *blocked_queue_tl;
-StgTSO *ccalling_threads;
-#define MAX_SCHEDULE_NESTING 256
-nat next_main_thread;
-StgTSO *main_threads[MAX_SCHEDULE_NESTING];
+#endif
+
+/* Linked list of all threads.
+ * Used for detecting garbage collected threads.
+ */
+StgTSO *all_threads;
+
+/* Threads suspended in _ccall_GC.
+ */
+static StgTSO *suspended_ccalling_threads;
static void GetRoots(void);
static StgTSO *threadStackOverflow(StgTSO *tso);
+/* KH: The following two flags are shared memory locations. There is no need
+ to lock them, since they are only unset at the end of a scheduler
+ operation.
+*/
+
/* flag set by signal handler to precipitate a context switch */
+//@cindex context_switch
nat context_switch;
+
/* if this flag is set as well, give up execution */
-static nat interrupted;
+//@cindex interrupted
+rtsBool interrupted;
-/* Next thread ID to allocate */
+/* Next thread ID to allocate.
+ * Locks required: sched_mutex
+ */
+//@cindex next_thread_id
StgThreadID next_thread_id = 1;
/*
* Rule of thumb: if CurrentTSO != NULL, then we're running a Haskell
* thread. If CurrentTSO == NULL, then we're at the scheduler level.
*/
-StgTSO *CurrentTSO;
-StgRegTable MainRegTable;
-
-/*
- * The thread state for the main thread.
- */
-StgTSO *MainTSO;
-
+
/* The smallest stack size that makes any sense is:
* RESERVED_STACK_WORDS (so we can get back from the stack overflow)
* + sizeofW(StgStopFrame) (the stg_stop_thread_info frame)
#define MIN_STACK_WORDS (RESERVED_STACK_WORDS + sizeofW(StgStopFrame) + 2)
-/* -----------------------------------------------------------------------------
- * Static functions
- * -------------------------------------------------------------------------- */
-static void unblockThread(StgTSO *tso);
-
-/* -----------------------------------------------------------------------------
- Create a new thread.
-
- The new thread starts with the given stack size. Before the
- scheduler can run, however, this thread needs to have a closure
- (and possibly some arguments) pushed on its stack. See
- pushClosure() in Schedule.h.
-
- createGenThread() and createIOThread() (in SchedAPI.h) are
- convenient packaged versions of this function.
- -------------------------------------------------------------------------- */
-
-StgTSO *
-createThread(nat stack_size)
-{
- StgTSO *tso;
+/* Free capability list.
+ * Locks required: sched_mutex.
+ */
+#ifdef SMP
+//@cindex free_capabilities
+//@cindex n_free_capabilities
+Capability *free_capabilities; /* Available capabilities for running threads */
+nat n_free_capabilities; /* total number of available capabilities */
+#else
+//@cindex MainRegTable
+Capability MainRegTable; /* for non-SMP, we have one global capability */
+#endif
- /* catch ridiculously small stack sizes */
- if (stack_size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
- stack_size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
- }
+#if defined(GRAN)
+StgTSO *CurrentTSO;
+#endif
- tso = (StgTSO *)allocate(stack_size);
- TICK_ALLOC_TSO(stack_size-sizeofW(StgTSO),0);
-
- initThread(tso, stack_size - TSO_STRUCT_SIZEW);
- return tso;
-}
+rtsBool ready_to_gc;
-void
-initThread(StgTSO *tso, nat stack_size)
-{
- SET_INFO(tso,&TSO_info);
- tso->whatNext = ThreadEnterGHC;
- tso->id = next_thread_id++;
- tso->blocked_on = NULL;
+/* All our current task ids, saved in case we need to kill them later.
+ */
+#ifdef SMP
+//@cindex task_ids
+task_info *task_ids;
+#endif
- tso->splim = (P_)&(tso->stack) + RESERVED_STACK_WORDS;
- tso->stack_size = stack_size;
- tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
- - TSO_STRUCT_SIZEW;
- tso->sp = (P_)&(tso->stack) + stack_size;
+void addToBlockedQueue ( StgTSO *tso );
-#ifdef PROFILING
- tso->prof.CCCS = CCS_MAIN;
+static void schedule ( void );
+ void interruptStgRts ( void );
+#if defined(GRAN)
+static StgTSO * createThread_ ( nat size, rtsBool have_lock, StgInt pri );
+#else
+static StgTSO * createThread_ ( nat size, rtsBool have_lock );
#endif
- /* put a stop frame on the stack */
- tso->sp -= sizeofW(StgStopFrame);
- SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_MAIN);
- tso->su = (StgUpdateFrame*)tso->sp;
-
- IF_DEBUG(scheduler,belch("Initialised thread %ld, stack size = %lx words\n",
- tso->id, tso->stack_size));
+static void detectBlackHoles ( void );
- /* Put the new thread on the head of the runnable queue.
- * The caller of createThread better push an appropriate closure
- * on this thread's stack before the scheduler is invoked.
- */
- tso->link = run_queue_hd;
- run_queue_hd = tso;
- if (run_queue_tl == END_TSO_QUEUE) {
- run_queue_tl = tso;
- }
+#ifdef DEBUG
+static void sched_belch(char *s, ...);
+#endif
- IF_DEBUG(scheduler,printTSO(tso));
-}
+#ifdef SMP
+//@cindex sched_mutex
+//@cindex term_mutex
+//@cindex thread_ready_cond
+//@cindex gc_pending_cond
+pthread_mutex_t sched_mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_mutex_t term_mutex = PTHREAD_MUTEX_INITIALIZER;
+pthread_cond_t thread_ready_cond = PTHREAD_COND_INITIALIZER;
+pthread_cond_t gc_pending_cond = PTHREAD_COND_INITIALIZER;
+
+nat await_death;
+#endif
-/* -----------------------------------------------------------------------------
- * initScheduler()
- *
- * Initialise the scheduler. This resets all the queues - if the
- * queues contained any threads, they'll be garbage collected at the
- * next pass.
- * -------------------------------------------------------------------------- */
+#if defined(PAR)
+StgTSO *LastTSO;
+rtsTime TimeOfLastYield;
+#endif
-void initScheduler(void)
-{
- run_queue_hd = END_TSO_QUEUE;
- run_queue_tl = END_TSO_QUEUE;
- blocked_queue_hd = END_TSO_QUEUE;
- blocked_queue_tl = END_TSO_QUEUE;
- ccalling_threads = END_TSO_QUEUE;
- next_main_thread = 0;
+#if DEBUG
+char *whatNext_strs[] = {
+ "ThreadEnterGHC",
+ "ThreadRunGHC",
+ "ThreadEnterHugs",
+ "ThreadKilled",
+ "ThreadComplete"
+};
+
+char *threadReturnCode_strs[] = {
+ "HeapOverflow", /* might also be StackOverflow */
+ "StackOverflow",
+ "ThreadYielding",
+ "ThreadBlocked",
+ "ThreadFinished"
+};
+#endif
- context_switch = 0;
- interrupted = 0;
+/*
+ * The thread state for the main thread.
+// ToDo: check whether not needed any more
+StgTSO *MainTSO;
+ */
- enteredCAFs = END_CAF_LIST;
-}
+//@node Main scheduling loop, Suspend and Resume, Prototypes, Main scheduling code
+//@subsection Main scheduling loop
-/* -----------------------------------------------------------------------------
+/* ---------------------------------------------------------------------------
Main scheduling loop.
We use round-robin scheduling, each thread returning to the
scheduler loop when one of these conditions is detected:
- * stack overflow
* out of heap space
* timer expires (thread yields)
* thread blocks
* thread ends
- -------------------------------------------------------------------------- */
+ * stack overflow
-SchedulerStatus schedule(StgTSO *main, StgClosure **ret_val)
+ Locking notes: we acquire the scheduler lock once at the beginning
+ of the scheduler loop, and release it when
+
+ * running a thread, or
+ * waiting for work, or
+ * waiting for a GC to complete.
+
+ GRAN version:
+ In a GranSim setup this loop iterates over the global event queue.
+ This revolves around the global event queue, which determines what
+ to do next. Therefore, it's more complicated than either the
+ concurrent or the parallel (GUM) setup.
+
+ GUM version:
+ GUM iterates over incoming messages.
+ It starts with nothing to do (thus CurrentTSO == END_TSO_QUEUE),
+ and sends out a fish whenever it has nothing to do; in-between
+ doing the actual reductions (shared code below) it processes the
+ incoming messages and deals with delayed operations
+ (see PendingFetches).
+ This is not the ugliest code you could imagine, but it's bloody close.
+
+ ------------------------------------------------------------------------ */
+//@cindex schedule
+static void
+schedule( void )
{
StgTSO *t;
+ Capability *cap;
StgThreadReturnCode ret;
- StgTSO **MainTSO;
- rtsBool in_ccall_gc;
+#if defined(GRAN)
+ rtsEvent *event;
+#elif defined(PAR)
+ StgSparkPool *pool;
+ rtsSpark spark;
+ StgTSO *tso;
+ GlobalTaskId pe;
+#endif
+ rtsBool was_interrupted = rtsFalse;
+
+ ACQUIRE_LOCK(&sched_mutex);
- /* Return value is NULL by default, it is only filled in if the
- * main thread completes successfully.
- */
- if (ret_val) { *ret_val = NULL; }
+#if defined(GRAN)
- /* Save away a pointer to the main thread so that we can keep track
- * of it should a garbage collection happen. We keep a stack of
- * main threads in order to support scheduler re-entry. We can't
- * use the normal TSO linkage for this stack, because the main TSO
- * may need to be linked onto other queues.
- */
- main_threads[next_main_thread] = main;
- MainTSO = &main_threads[next_main_thread];
- next_main_thread++;
- IF_DEBUG(scheduler,
- fprintf(stderr, "Scheduler entered: nesting = %d\n",
- next_main_thread););
+ /* set up first event to get things going */
+ /* ToDo: assign costs for system setup and init MainTSO ! */
+ new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
+ ContinueThread,
+ CurrentTSO, (StgClosure*)NULL, (rtsSpark*)NULL);
- /* Are we being re-entered?
- */
- if (CurrentTSO != NULL) {
- /* This happens when a _ccall_gc from Haskell ends up re-entering
- * the scheduler.
- *
- * Block the current thread (put it on the ccalling_queue) and
- * continue executing. The calling thread better have stashed
- * away its state properly and left its stack with a proper stack
- * frame on the top.
- */
- threadPaused(CurrentTSO);
- CurrentTSO->link = ccalling_threads;
- ccalling_threads = CurrentTSO;
- in_ccall_gc = rtsTrue;
- IF_DEBUG(scheduler,
- fprintf(stderr, "Re-entry, thread %d did a _ccall_gc\n",
- CurrentTSO->id););
- } else {
- in_ccall_gc = rtsFalse;
- }
+ IF_DEBUG(gran,
+ fprintf(stderr, "GRAN: Init CurrentTSO (in schedule) = %p\n", CurrentTSO);
+ G_TSO(CurrentTSO, 5));
- /* Take a thread from the run queue.
- */
- t = run_queue_hd;
- if (t != END_TSO_QUEUE) {
- run_queue_hd = t->link;
- t->link = END_TSO_QUEUE;
- if (run_queue_hd == END_TSO_QUEUE) {
- run_queue_tl = END_TSO_QUEUE;
- }
- }
+ if (RtsFlags.GranFlags.Light) {
+ /* Save current time; GranSim Light only */
+ CurrentTSO->gran.clock = CurrentTime[CurrentProc];
+ }
- while (t != END_TSO_QUEUE) {
- CurrentTSO = t;
+ event = get_next_event();
- /* If we have more threads on the run queue, set up a context
- * switch at some point in the future.
- */
- if (run_queue_hd != END_TSO_QUEUE) {
- context_switch = 1;
- } else {
- context_switch = 0;
- }
- IF_DEBUG(scheduler, belch("Running thread %ld...\n", t->id));
+ while (event!=(rtsEvent*)NULL) {
+ /* Choose the processor with the next event */
+ CurrentProc = event->proc;
+ CurrentTSO = event->tso;
- /* Be friendly to the storage manager: we're about to *run* this
- * thread, so we better make sure the TSO is mutable.
- */
- if (t->mut_link == NULL) {
- recordMutable((StgMutClosure *)t);
- }
+#elif defined(PAR)
+
+ while (!GlobalStopPending) { /* GlobalStopPending set in par_exit */
- /* Run the current thread */
- switch (t->whatNext) {
- case ThreadKilled:
- case ThreadComplete:
- /* thread already killed. Drop it and carry on. */
- goto next_thread;
- case ThreadEnterGHC:
- ret = StgRun((StgFunPtr) stg_enterStackTop);
- break;
- case ThreadRunGHC:
- ret = StgRun((StgFunPtr) stg_returnToStackTop);
- break;
- case ThreadEnterHugs:
-#ifdef INTERPRETER
- {
- IF_DEBUG(scheduler,belch("entering Hugs"));
- LoadThreadState();
- /* CHECK_SENSIBLE_REGS(); */
- {
- StgClosure* c = (StgClosure *)Sp[0];
- Sp += 1;
- ret = enter(c);
- }
- SaveThreadState();
- break;
- }
#else
- barf("Panic: entered a BCO but no bytecode interpreter in this build");
-#endif
- default:
- barf("schedule: invalid whatNext field");
- }
- /* We may have garbage collected while running the thread
- * (eg. something nefarious like _ccall_GC_ performGC), and hence
- * CurrentTSO may have moved. Update t to reflect this.
- */
- t = CurrentTSO;
- CurrentTSO = NULL;
+ while (1) {
- /* Costs for the scheduler are assigned to CCS_SYSTEM */
-#ifdef PROFILING
- CCCS = CCS_SYSTEM;
#endif
- switch (ret) {
+ IF_DEBUG(scheduler, printAllThreads());
- case HeapOverflow:
- IF_DEBUG(scheduler,belch("Thread %ld stopped: HeapOverflow\n", t->id));
- threadPaused(t);
- PUSH_ON_RUN_QUEUE(t);
- GarbageCollect(GetRoots);
- break;
+ /* If we're interrupted (the user pressed ^C, or some other
+ * termination condition occurred), kill all the currently running
+ * threads.
+ */
+ if (interrupted) {
+ IF_DEBUG(scheduler, sched_belch("interrupted"));
+ for (t = run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
+ deleteThread(t);
+ }
+ for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = t->link) {
+ deleteThread(t);
+ }
+ run_queue_hd = run_queue_tl = END_TSO_QUEUE;
+ blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
+ interrupted = rtsFalse;
+ was_interrupted = rtsTrue;
+ }
- case StackOverflow:
- IF_DEBUG(scheduler,belch("Thread %ld stopped, StackOverflow\n", t->id));
- {
- nat i;
- /* enlarge the stack */
- StgTSO *new_t = threadStackOverflow(t);
-
- /* This TSO has moved, so update any pointers to it from the
- * main thread stack. It better not be on any other queues...
- * (it shouldn't be)
- */
- for (i = 0; i < next_main_thread; i++) {
- if (main_threads[i] == t) {
- main_threads[i] = new_t;
+ /* Go through the list of main threads and wake up any
+ * clients whose computations have finished. ToDo: this
+ * should be done more efficiently without a linear scan
+ * of the main threads list, somehow...
+ */
+#ifdef SMP
+ {
+ StgMainThread *m, **prev;
+ prev = &main_threads;
+ for (m = main_threads; m != NULL; m = m->link) {
+ switch (m->tso->what_next) {
+ case ThreadComplete:
+ if (m->ret) {
+ *(m->ret) = (StgClosure *)m->tso->sp[0];
}
+ *prev = m->link;
+ m->stat = Success;
+ pthread_cond_broadcast(&m->wakeup);
+ break;
+ case ThreadKilled:
+ *prev = m->link;
+ if (was_interrupted) {
+ m->stat = Interrupted;
+ } else {
+ m->stat = Killed;
+ }
+ pthread_cond_broadcast(&m->wakeup);
+ break;
+ default:
+ break;
}
- t = new_t;
}
- PUSH_ON_RUN_QUEUE(t);
- break;
+ }
- case ThreadYielding:
- IF_DEBUG(scheduler,
- if (t->whatNext == ThreadEnterHugs) {
- /* ToDo: or maybe a timer expired when we were in Hugs?
- * or maybe someone hit ctrl-C
- */
- belch("Thread %ld stopped to switch to Hugs\n", t->id);
- } else {
- belch("Thread %ld stopped, timer expired\n", t->id);
- }
- );
- threadPaused(t);
- if (interrupted) {
- IF_DEBUG(scheduler,belch("Scheduler interrupted - returning"));
- deleteThread(t);
- while (run_queue_hd != END_TSO_QUEUE) {
- run_queue_hd = t->link;
- deleteThread(t);
+#else
+# if defined(PAR)
+ /* in GUM do this only on the Main PE */
+ if (IAmMainThread)
+# endif
+ /* If our main thread has finished or been killed, return.
+ */
+ {
+ StgMainThread *m = main_threads;
+ if (m->tso->what_next == ThreadComplete
+ || m->tso->what_next == ThreadKilled) {
+ main_threads = main_threads->link;
+ if (m->tso->what_next == ThreadComplete) {
+ /* we finished successfully, fill in the return value */
+ if (m->ret) { *(m->ret) = (StgClosure *)m->tso->sp[0]; };
+ m->stat = Success;
+ return;
+ } else {
+ if (was_interrupted) {
+ m->stat = Interrupted;
+ } else {
+ m->stat = Killed;
}
- run_queue_tl = END_TSO_QUEUE;
- /* ToDo: should I do the same with blocked queues? */
- return Interrupted;
+ return;
+ }
}
+ }
+#endif
- /* Put the thread back on the run queue, at the end.
- * t->link is already set to END_TSO_QUEUE.
- */
- ASSERT(t->link == END_TSO_QUEUE);
- if (run_queue_tl == END_TSO_QUEUE) {
- run_queue_hd = run_queue_tl = t;
- } else {
- ASSERT(get_itbl(run_queue_tl)->type == TSO);
- if (run_queue_hd == run_queue_tl) {
- run_queue_hd->link = t;
- run_queue_tl = t;
+ /* Top up the run queue from our spark pool. We try to make the
+ * number of threads in the run queue equal to the number of
+ * free capabilities.
+ */
+#if defined(SMP)
+ {
+ nat n = n_free_capabilities;
+ StgTSO *tso = run_queue_hd;
+
+ /* Count the run queue */
+ while (n > 0 && tso != END_TSO_QUEUE) {
+ tso = tso->link;
+ n--;
+ }
+
+ for (; n > 0; n--) {
+ StgClosure *spark;
+ spark = findSpark();
+ if (spark == NULL) {
+ break; /* no more sparks in the pool */
} else {
- run_queue_tl->link = t;
- run_queue_tl = t;
+ /* I'd prefer this to be done in activateSpark -- HWL */
+ /* tricky - it needs to hold the scheduler lock and
+ * not try to re-acquire it -- SDM */
+ StgTSO *tso;
+ tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue);
+ pushClosure(tso,spark);
+ PUSH_ON_RUN_QUEUE(tso);
+#ifdef PAR
+ advisory_thread_count++;
+#endif
+
+ IF_DEBUG(scheduler,
+ sched_belch("turning spark of closure %p into a thread",
+ (StgClosure *)spark));
}
}
- break;
-
- case ThreadBlocked:
- IF_DEBUG(scheduler,belch("Thread %ld stopped, blocking\n", t->id));
- threadPaused(t);
- /* assume the thread has put itself on some blocked queue
- * somewhere.
+ /* We need to wake up the other tasks if we just created some
+ * work for them.
*/
- break;
-
- case ThreadFinished:
- IF_DEBUG(scheduler,belch("Thread %ld finished\n", t->id));
- t->whatNext = ThreadComplete;
- break;
-
- default:
- barf("schedule: invalid thread return code");
+ if (n_free_capabilities - n > 1) {
+ pthread_cond_signal(&thread_ready_cond);
+ }
}
+#endif /* SMP */
+ /* Check whether any waiting threads need to be woken up. If the
+ * run queue is empty, and there are no other tasks running, we
+ * can wait indefinitely for something to happen.
+ * ToDo: what if another client comes along & requests another
+ * main thread?
+ */
+ if (blocked_queue_hd != END_TSO_QUEUE) {
+ awaitEvent(
+ (run_queue_hd == END_TSO_QUEUE)
+#ifdef SMP
+ && (n_free_capabilities == RtsFlags.ParFlags.nNodes)
+#endif
+ );
+ }
+
/* check for signals each time around the scheduler */
-#ifndef __MINGW32__
+#ifndef mingw32_TARGET_OS
if (signals_pending()) {
start_signal_handlers();
}
#endif
- /* If our main thread has finished or been killed, return.
- * If we were re-entered as a result of a _ccall_gc, then
- * pop the blocked thread off the ccalling_threads stack back
- * into CurrentTSO.
+
+ /*
+ * Detect deadlock: when we have no threads to run, there are no
+ * threads waiting on I/O or sleeping, and all the other tasks are
+ * waiting for work, we must have a deadlock of some description.
+ *
+ * We first try to find threads blocked on themselves (ie. black
+ * holes), and generate NonTermination exceptions where necessary.
+ *
+ * If no threads are black holed, we have a deadlock situation, so
+ * inform all the main threads.
*/
- if ((*MainTSO)->whatNext == ThreadComplete
- || (*MainTSO)->whatNext == ThreadKilled) {
- next_main_thread--;
- if (in_ccall_gc) {
- CurrentTSO = ccalling_threads;
- ccalling_threads = ccalling_threads->link;
- /* remember to stub the link field of CurrentTSO */
- CurrentTSO->link = END_TSO_QUEUE;
- }
- if ((*MainTSO)->whatNext == ThreadComplete) {
- /* we finished successfully, fill in the return value */
- if (ret_val) { *ret_val = (StgClosure *)(*MainTSO)->sp[0]; };
- return Success;
- } else {
- return Killed;
- }
+#ifdef SMP
+ if (blocked_queue_hd == END_TSO_QUEUE
+ && run_queue_hd == END_TSO_QUEUE
+ && (n_free_capabilities == RtsFlags.ParFlags.nNodes))
+ {
+ IF_DEBUG(scheduler, sched_belch("deadlocked, checking for black holes..."));
+ detectBlackHoles();
+ if (run_queue_hd == END_TSO_QUEUE) {
+ StgMainThread *m;
+ for (m = main_threads; m != NULL; m = m->link) {
+ m->ret = NULL;
+ m->stat = Deadlock;
+ pthread_cond_broadcast(&m->wakeup);
+ }
+ main_threads = NULL;
+ }
+ }
+#else /* ! SMP */
+ if (blocked_queue_hd == END_TSO_QUEUE
+ && run_queue_hd == END_TSO_QUEUE)
+ {
+ IF_DEBUG(scheduler, sched_belch("deadlocked, checking for black holes..."));
+ detectBlackHoles();
+ if (run_queue_hd == END_TSO_QUEUE) {
+ StgMainThread *m = main_threads;
+ m->ret = NULL;
+ m->stat = Deadlock;
+ main_threads = m->link;
+ return;
+ }
}
+#endif
- next_thread:
- t = run_queue_hd;
- if (t != END_TSO_QUEUE) {
- run_queue_hd = t->link;
- t->link = END_TSO_QUEUE;
- if (run_queue_hd == END_TSO_QUEUE) {
- run_queue_tl = END_TSO_QUEUE;
- }
+#ifdef SMP
+ /* If there's a GC pending, don't do anything until it has
+ * completed.
+ */
+ if (ready_to_gc) {
+ IF_DEBUG(scheduler,sched_belch("waiting for GC"));
+ pthread_cond_wait(&gc_pending_cond, &sched_mutex);
}
- }
+
+ /* block until we've got a thread on the run queue and a free
+ * capability.
+ */
+ while (run_queue_hd == END_TSO_QUEUE || free_capabilities == NULL) {
+ IF_DEBUG(scheduler, sched_belch("waiting for work"));
+ pthread_cond_wait(&thread_ready_cond, &sched_mutex);
+ IF_DEBUG(scheduler, sched_belch("work now available"));
+ }
+#endif
- if (blocked_queue_hd != END_TSO_QUEUE) {
- return AllBlocked;
- } else {
- return Deadlock;
- }
-}
+#if defined(GRAN)
-/* -----------------------------------------------------------------------------
- Where are the roots that we know about?
+ if (RtsFlags.GranFlags.Light)
+ GranSimLight_enter_system(event, &ActiveTSO); // adjust ActiveTSO etc
- - all the threads on the runnable queue
- - all the threads on the blocked queue
- - all the thread currently executing a _ccall_GC
- - all the "main threads"
-
+ /* adjust time based on time-stamp */
+ if (event->time > CurrentTime[CurrentProc] &&
+ event->evttype != ContinueThread)
+ CurrentTime[CurrentProc] = event->time;
+
+ /* Deal with the idle PEs (may issue FindWork or MoveSpark events) */
+ if (!RtsFlags.GranFlags.Light)
+ handleIdlePEs();
+
+ IF_DEBUG(gran, fprintf(stderr, "GRAN: switch by event-type\n"))
+
+ /* main event dispatcher in GranSim */
+ switch (event->evttype) {
+ /* Should just be continuing execution */
+ case ContinueThread:
+ IF_DEBUG(gran, fprintf(stderr, "GRAN: doing ContinueThread\n"));
+ /* ToDo: check assertion
+ ASSERT(run_queue_hd != (StgTSO*)NULL &&
+ run_queue_hd != END_TSO_QUEUE);
+ */
+ /* Ignore ContinueThreads for fetching threads (if synchr comm) */
+ if (!RtsFlags.GranFlags.DoAsyncFetch &&
+ procStatus[CurrentProc]==Fetching) {
+ belch("ghuH: Spurious ContinueThread while Fetching ignored; TSO %d (%p) [PE %d]",
+ CurrentTSO->id, CurrentTSO, CurrentProc);
+ goto next_thread;
+ }
+ /* Ignore ContinueThreads for completed threads */
+ if (CurrentTSO->what_next == ThreadComplete) {
+ belch("ghuH: found a ContinueThread event for completed thread %d (%p) [PE %d] (ignoring ContinueThread)",
+ CurrentTSO->id, CurrentTSO, CurrentProc);
+ goto next_thread;
+ }
+ /* Ignore ContinueThreads for threads that are being migrated */
+ if (PROCS(CurrentTSO)==Nowhere) {
+ belch("ghuH: trying to run the migrating TSO %d (%p) [PE %d] (ignoring ContinueThread)",
+ CurrentTSO->id, CurrentTSO, CurrentProc);
+ goto next_thread;
+ }
+ /* The thread should be at the beginning of the run queue */
+ if (CurrentTSO!=run_queue_hds[CurrentProc]) {
+ belch("ghuH: TSO %d (%p) [PE %d] is not at the start of the run_queue when doing a ContinueThread",
+ CurrentTSO->id, CurrentTSO, CurrentProc);
+ break; // run the thread anyway
+ }
+ /*
+ new_event(proc, proc, CurrentTime[proc],
+ FindWork,
+ (StgTSO*)NULL, (StgClosure*)NULL, (rtsSpark*)NULL);
+ goto next_thread;
+ */ /* Catches superfluous CONTINUEs -- should be unnecessary */
+ break; // now actually run the thread; DaH Qu'vam yImuHbej
+
+ case FetchNode:
+ do_the_fetchnode(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case GlobalBlock:
+ do_the_globalblock(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case FetchReply:
+ do_the_fetchreply(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case UnblockThread: /* Move from the blocked queue to the tail of */
+ do_the_unblock(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case ResumeThread: /* Move from the blocked queue to the tail of */
+ /* the runnable queue ( i.e. Qu' SImqa'lu') */
+ event->tso->gran.blocktime +=
+ CurrentTime[CurrentProc] - event->tso->gran.blockedat;
+ do_the_startthread(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case StartThread:
+ do_the_startthread(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case MoveThread:
+ do_the_movethread(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case MoveSpark:
+ do_the_movespark(event);
+ goto next_thread; /* handle next event in event queue */
+
+ case FindWork:
+ do_the_findwork(event);
+ goto next_thread; /* handle next event in event queue */
+
+ default:
+ barf("Illegal event type %u\n", event->evttype);
+ } /* switch */
+
+ /* This point was scheduler_loop in the old RTS */
+
+ IF_DEBUG(gran, belch("GRAN: after main switch"));
+
+ TimeOfLastEvent = CurrentTime[CurrentProc];
+ TimeOfNextEvent = get_time_of_next_event();
+ IgnoreEvents=(TimeOfNextEvent==0); // HWL HACK
+ // CurrentTSO = ThreadQueueHd;
+
+ IF_DEBUG(gran, belch("GRAN: time of next event is: %ld",
+ TimeOfNextEvent));
+
+ if (RtsFlags.GranFlags.Light)
+ GranSimLight_leave_system(event, &ActiveTSO);
+
+ EndOfTimeSlice = CurrentTime[CurrentProc]+RtsFlags.GranFlags.time_slice;
+
+ IF_DEBUG(gran,
+ belch("GRAN: end of time-slice is %#lx", EndOfTimeSlice));
+
+ /* in a GranSim setup the TSO stays on the run queue */
+ t = CurrentTSO;
+ /* Take a thread from the run queue. */
+ t = POP_RUN_QUEUE(); // take_off_run_queue(t);
+
+ IF_DEBUG(gran,
+ fprintf(stderr, "GRAN: About to run current thread, which is\n");
+ G_TSO(t,5))
+
+ context_switch = 0; // turned on via GranYield, checking events and time slice
+
+ IF_DEBUG(gran,
+ DumpGranEvent(GR_SCHEDULE, t));
+
+ procStatus[CurrentProc] = Busy;
+
+#elif defined(PAR)
+
+ if (PendingFetches != END_BF_QUEUE) {
+ processFetches();
+ }
+
+ /* ToDo: phps merge with spark activation above */
+ /* check whether we have local work and send requests if we have none */
+ if (run_queue_hd == END_TSO_QUEUE) { /* no runnable threads */
+ /* :-[ no local threads => look out for local sparks */
+ /* the spark pool for the current PE */
+ pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
+ if (advisory_thread_count < RtsFlags.ParFlags.maxThreads &&
+ pool->hd < pool->tl) {
+ /*
+ * ToDo: add GC code check that we really have enough heap afterwards!!
+ * Old comment:
+ * If we're here (no runnable threads) and we have pending
+ * sparks, we must have a space problem. Get enough space
+ * to turn one of those pending sparks into a
+ * thread...
+ */
+
+ spark = findSpark(); /* get a spark */
+ if (spark != (rtsSpark) NULL) {
+ tso = activateSpark(spark); /* turn the spark into a thread */
+ IF_PAR_DEBUG(schedule,
+ belch("==== schedule: Created TSO %d (%p); %d threads active",
+ tso->id, tso, advisory_thread_count));
+
+ if (tso==END_TSO_QUEUE) { /* failed to activate spark->back to loop */
+ belch("==^^ failed to activate spark");
+ goto next_thread;
+ } /* otherwise fall through & pick-up new tso */
+ } else {
+ IF_PAR_DEBUG(verbose,
+ belch("==^^ no local sparks (spark pool contains only NFs: %d)",
+ spark_queue_len(pool)));
+ goto next_thread;
+ }
+ } else
+ /* =8-[ no local sparks => look for work on other PEs */
+ {
+ /*
+ * We really have absolutely no work. Send out a fish
+ * (there may be some out there already), and wait for
+ * something to arrive. We clearly can't run any threads
+ * until a SCHEDULE or RESUME arrives, and so that's what
+ * we're hoping to see. (Of course, we still have to
+ * respond to other types of messages.)
+ */
+ if (//!fishing &&
+ outstandingFishes < RtsFlags.ParFlags.maxFishes ) { // &&
+ // (last_fish_arrived_at+FISH_DELAY < CURRENT_TIME)) {
+ /* fishing set in sendFish, processFish;
+ avoid flooding system with fishes via delay */
+ pe = choosePE();
+ sendFish(pe, mytid, NEW_FISH_AGE, NEW_FISH_HISTORY,
+ NEW_FISH_HUNGER);
+ }
+
+ processMessages();
+ goto next_thread;
+ // ReSchedule(0);
+ }
+ } else if (PacketsWaiting()) { /* Look for incoming messages */
+ processMessages();
+ }
+
+ /* Now we are sure that we have some work available */
+ ASSERT(run_queue_hd != END_TSO_QUEUE);
+ /* Take a thread from the run queue, if we have work */
+ t = POP_RUN_QUEUE(); // take_off_run_queue(END_TSO_QUEUE);
+
+ /* ToDo: write something to the log-file
+ if (RTSflags.ParFlags.granSimStats && !sameThread)
+ DumpGranEvent(GR_SCHEDULE, RunnableThreadsHd);
+
+ CurrentTSO = t;
+ */
+ /* the spark pool for the current PE */
+ pool = &(MainRegTable.rSparks); // generalise to cap = &MainRegTable
+
+ IF_DEBUG(scheduler, belch("--^^ %d sparks on [%#x] (hd=%x; tl=%x; base=%x, lim=%x)",
+ spark_queue_len(pool),
+ CURRENT_PROC,
+ pool->hd, pool->tl, pool->base, pool->lim));
+
+ IF_DEBUG(scheduler, belch("--== %d threads on [%#x] (hd=%x; tl=%x)",
+ run_queue_len(), CURRENT_PROC,
+ run_queue_hd, run_queue_tl));
+
+#if 0
+ if (t != LastTSO) {
+ /*
+ we are running a different TSO, so write a schedule event to log file
+ NB: If we use fair scheduling we also have to write a deschedule
+ event for LastTSO; with unfair scheduling we know that the
+ previous tso has blocked whenever we switch to another tso, so
+ we don't need it in GUM for now
+ */
+ DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
+ GR_SCHEDULE, t, (StgClosure *)NULL, 0, 0);
+
+ }
+#endif
+#else /* !GRAN && !PAR */
+
+ /* grab a thread from the run queue
+ */
+ ASSERT(run_queue_hd != END_TSO_QUEUE);
+ t = POP_RUN_QUEUE();
+ IF_DEBUG(sanity,checkTSO(t));
+
+#endif
+
+ /* grab a capability
+ */
+#ifdef SMP
+ cap = free_capabilities;
+ free_capabilities = cap->link;
+ n_free_capabilities--;
+#else
+ cap = &MainRegTable;
+#endif
+
+ cap->rCurrentTSO = t;
+
+ /* context switches are now initiated by the timer signal, unless
+ * the user specified "context switch as often as possible", with
+ * +RTS -C0
+ */
+ if (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
+ && (run_queue_hd != END_TSO_QUEUE
+ || blocked_queue_hd != END_TSO_QUEUE))
+ context_switch = 1;
+ else
+ context_switch = 0;
+
+ RELEASE_LOCK(&sched_mutex);
+
+ IF_DEBUG(scheduler, sched_belch("-->> Running TSO %ld (%p) %s ...",
+ t->id, t, whatNext_strs[t->what_next]));
+
+ /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
+ /* Run the current thread
+ */
+ switch (cap->rCurrentTSO->what_next) {
+ case ThreadKilled:
+ case ThreadComplete:
+ /* Thread already finished, return to scheduler. */
+ ret = ThreadFinished;
+ break;
+ case ThreadEnterGHC:
+ ret = StgRun((StgFunPtr) stg_enterStackTop, cap);
+ break;
+ case ThreadRunGHC:
+ ret = StgRun((StgFunPtr) stg_returnToStackTop, cap);
+ break;
+ case ThreadEnterHugs:
+#ifdef INTERPRETER
+ {
+ StgClosure* c;
+ IF_DEBUG(scheduler,sched_belch("entering Hugs"));
+ c = (StgClosure *)(cap->rCurrentTSO->sp[0]);
+ cap->rCurrentTSO->sp += 1;
+ ret = enter(cap,c);
+ break;
+ }
+#else
+ barf("Panic: entered a BCO but no bytecode interpreter in this build");
+#endif
+ default:
+ barf("schedule: invalid what_next field");
+ }
+ /* +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ */
+
+ /* Costs for the scheduler are assigned to CCS_SYSTEM */
+#ifdef PROFILING
+ CCCS = CCS_SYSTEM;
+#endif
+
+ ACQUIRE_LOCK(&sched_mutex);
+
+#ifdef SMP
+ IF_DEBUG(scheduler,fprintf(stderr,"scheduler (task %ld): ", pthread_self()););
+#elif !defined(GRAN) && !defined(PAR)
+ IF_DEBUG(scheduler,fprintf(stderr,"scheduler: "););
+#endif
+ t = cap->rCurrentTSO;
+
+#if defined(PAR)
+ /* HACK 675: if the last thread didn't yield, make sure to print a
+ SCHEDULE event to the log file when StgRunning the next thread, even
+ if it is the same one as before */
+ LastTSO = t; //(ret == ThreadBlocked) ? END_TSO_QUEUE : t;
+ TimeOfLastYield = CURRENT_TIME;
+#endif
+
+ switch (ret) {
+ case HeapOverflow:
+ /* make all the running tasks block on a condition variable,
+ * maybe set context_switch and wait till they all pile in,
+ * then have them wait on a GC condition variable.
+ */
+ IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped: HeapOverflow",
+ t->id, t, whatNext_strs[t->what_next]));
+ threadPaused(t);
+#if defined(GRAN)
+ ASSERT(!is_on_queue(t,CurrentProc));
+#endif
+
+ ready_to_gc = rtsTrue;
+ context_switch = 1; /* stop other threads ASAP */
+ PUSH_ON_RUN_QUEUE(t);
+ /* actual GC is done at the end of the while loop */
+ break;
+
+ case StackOverflow:
+ IF_DEBUG(scheduler,belch("--<< thread %ld (%p; %s) stopped, StackOverflow",
+ t->id, t, whatNext_strs[t->what_next]));
+ /* just adjust the stack for this thread, then pop it back
+ * on the run queue.
+ */
+ threadPaused(t);
+ {
+ StgMainThread *m;
+ /* enlarge the stack */
+ StgTSO *new_t = threadStackOverflow(t);
+
+ /* This TSO has moved, so update any pointers to it from the
+ * main thread stack. It better not be on any other queues...
+ * (it shouldn't be).
+ */
+ for (m = main_threads; m != NULL; m = m->link) {
+ if (m->tso == t) {
+ m->tso = new_t;
+ }
+ }
+ threadPaused(new_t);
+ PUSH_ON_RUN_QUEUE(new_t);
+ }
+ break;
+
+ case ThreadYielding:
+#if defined(GRAN)
+ IF_DEBUG(gran,
+ DumpGranEvent(GR_DESCHEDULE, t));
+ globalGranStats.tot_yields++;
+#elif defined(PAR)
+ IF_DEBUG(par,
+ DumpGranEvent(GR_DESCHEDULE, t));
+#endif
+ /* put the thread back on the run queue. Then, if we're ready to
+ * GC, check whether this is the last task to stop. If so, wake
+ * up the GC thread. getThread will block during a GC until the
+ * GC is finished.
+ */
+ IF_DEBUG(scheduler,
+ if (t->what_next == ThreadEnterHugs) {
+ /* ToDo: or maybe a timer expired when we were in Hugs?
+ * or maybe someone hit ctrl-C
+ */
+ belch("--<< thread %ld (%p; %s) stopped to switch to Hugs",
+ t->id, t, whatNext_strs[t->what_next]);
+ } else {
+ belch("--<< thread %ld (%p; %s) stopped, yielding",
+ t->id, t, whatNext_strs[t->what_next]);
+ }
+ );
+
+ threadPaused(t);
+
+ IF_DEBUG(sanity,
+ //belch("&& Doing sanity check on yielding TSO %ld.", t->id);
+ checkTSO(t));
+ ASSERT(t->link == END_TSO_QUEUE);
+#if defined(GRAN)
+ ASSERT(!is_on_queue(t,CurrentProc));
+
+ IF_DEBUG(sanity,
+ //belch("&& Doing sanity check on all ThreadQueues (and their TSOs).");
+ checkThreadQsSanity(rtsTrue));
+#endif
+ APPEND_TO_RUN_QUEUE(t);
+#if defined(GRAN)
+ /* add a ContinueThread event to actually process the thread */
+ new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
+ ContinueThread,
+ t, (StgClosure*)NULL, (rtsSpark*)NULL);
+ IF_GRAN_DEBUG(bq,
+ belch("GRAN: eventq and runnableq after adding yielded thread to queue again:");
+ G_EVENTQ(0);
+ G_CURR_THREADQ(0))
+#endif /* GRAN */
+ break;
+
+ case ThreadBlocked:
+#if defined(GRAN)
+ IF_DEBUG(scheduler,
+ belch("--<< thread %ld (%p; %s) stopped, blocking on node %p [PE %d] with BQ: ",
+ t->id, t, whatNext_strs[t->what_next], t->block_info.closure, (t->block_info.closure==(StgClosure*)NULL ? 99 : where_is(t->block_info.closure)));
+ if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
+
+ // ??? needed; should emit block before
+ IF_DEBUG(gran,
+ DumpGranEvent(GR_DESCHEDULE, t));
+ prune_eventq(t, (StgClosure *)NULL); // prune ContinueThreads for t
+ /*
+ ngoq Dogh!
+ ASSERT(procStatus[CurrentProc]==Busy ||
+ ((procStatus[CurrentProc]==Fetching) &&
+ (t->block_info.closure!=(StgClosure*)NULL)));
+ if (run_queue_hds[CurrentProc] == END_TSO_QUEUE &&
+ !(!RtsFlags.GranFlags.DoAsyncFetch &&
+ procStatus[CurrentProc]==Fetching))
+ procStatus[CurrentProc] = Idle;
+ */
+#elif defined(PAR)
+ IF_DEBUG(par,
+ DumpGranEvent(GR_DESCHEDULE, t));
+
+ /* Send a fetch (if BlockedOnGA) and dump event to log file */
+ blockThread(t);
+
+ IF_DEBUG(scheduler,
+ belch("--<< thread %ld (%p; %s) stopped, blocking on node %p with BQ: ",
+ t->id, t, whatNext_strs[t->what_next], t->block_info.closure);
+ if (t->block_info.closure!=(StgClosure*)NULL) print_bq(t->block_info.closure));
+
+#else /* !GRAN */
+ /* don't need to do anything. Either the thread is blocked on
+ * I/O, in which case we'll have called addToBlockedQueue
+ * previously, or it's blocked on an MVar or Blackhole, in which
+ * case it'll be on the relevant queue already.
+ */
+ IF_DEBUG(scheduler,
+ fprintf(stderr, "--<< thread %d (%p) stopped: ", t->id, t);
+ printThreadBlockage(t);
+ fprintf(stderr, "\n"));
+
+ /* Only for dumping event to log file
+ ToDo: do I need this in GranSim, too?
+ blockThread(t);
+ */
+#endif
+ threadPaused(t);
+ break;
+
+ case ThreadFinished:
+ /* Need to check whether this was a main thread, and if so, signal
+ * the task that started it with the return value. If we have no
+ * more main threads, we probably need to stop all the tasks until
+ * we get a new one.
+ */
+ /* We also end up here if the thread kills itself with an
+ * uncaught exception, see Exception.hc.
+ */
+ IF_DEBUG(scheduler,belch("--++ thread %d (%p) finished", t->id, t));
+#if defined(GRAN)
+ endThread(t, CurrentProc); // clean-up the thread
+#elif defined(PAR)
+ advisory_thread_count--;
+ if (RtsFlags.ParFlags.ParStats.Full)
+ DumpEndEvent(CURRENT_PROC, t, rtsFalse /* not mandatory */);
+#endif
+ break;
+
+ default:
+ barf("schedule: invalid thread return code %d", (int)ret);
+ }
+
+#ifdef SMP
+ cap->link = free_capabilities;
+ free_capabilities = cap;
+ n_free_capabilities++;
+#endif
+
+#ifdef SMP
+ if (ready_to_gc && n_free_capabilities == RtsFlags.ParFlags.nNodes)
+#else
+ if (ready_to_gc)
+#endif
+ {
+ /* everybody back, start the GC.
+ * Could do it in this thread, or signal a condition var
+ * to do it in another thread. Either way, we need to
+ * broadcast on gc_pending_cond afterward.
+ */
+#ifdef SMP
+ IF_DEBUG(scheduler,sched_belch("doing GC"));
+#endif
+ GarbageCollect(GetRoots,rtsFalse);
+ ready_to_gc = rtsFalse;
+#ifdef SMP
+ pthread_cond_broadcast(&gc_pending_cond);
+#endif
+#if defined(GRAN)
+ /* add a ContinueThread event to continue execution of current thread */
+ new_event(CurrentProc, CurrentProc, CurrentTime[CurrentProc],
+ ContinueThread,
+ t, (StgClosure*)NULL, (rtsSpark*)NULL);
+ IF_GRAN_DEBUG(bq,
+ fprintf(stderr, "GRAN: eventq and runnableq after Garbage collection:\n");
+ G_EVENTQ(0);
+ G_CURR_THREADQ(0))
+#endif /* GRAN */
+ }
+#if defined(GRAN)
+ next_thread:
+ IF_GRAN_DEBUG(unused,
+ print_eventq(EventHd));
+
+ event = get_next_event();
+
+#elif defined(PAR)
+ next_thread:
+ /* ToDo: wait for next message to arrive rather than busy wait */
+
+#else /* GRAN */
+ /* not any more
+ next_thread:
+ t = take_off_run_queue(END_TSO_QUEUE);
+ */
+#endif /* GRAN */
+ } /* end of while(1) */
+}
+
+/* A hack for Hugs concurrency support. Needs sanitisation (?) */
+void deleteAllThreads ( void )
+{
+ StgTSO* t;
+ IF_DEBUG(scheduler,sched_belch("deleteAllThreads()"));
+ for (t = run_queue_hd; t != END_TSO_QUEUE; t = t->link) {
+ deleteThread(t);
+ }
+ for (t = blocked_queue_hd; t != END_TSO_QUEUE; t = t->link) {
+ deleteThread(t);
+ }
+ run_queue_hd = run_queue_tl = END_TSO_QUEUE;
+ blocked_queue_hd = blocked_queue_tl = END_TSO_QUEUE;
+}
+
+/* startThread and insertThread are now in GranSim.c -- HWL */
+
+//@node Suspend and Resume, Run queue code, Main scheduling loop, Main scheduling code
+//@subsection Suspend and Resume
+
+/* ---------------------------------------------------------------------------
+ * Suspending & resuming Haskell threads.
+ *
+ * When making a "safe" call to C (aka _ccall_GC), the task gives back
+ * its capability before calling the C function. This allows another
+ * task to pick up the capability and carry on running Haskell
+ * threads. It also means that if the C call blocks, it won't lock
+ * the whole system.
+ *
+ * The Haskell thread making the C call is put to sleep for the
+ * duration of the call, on the susepended_ccalling_threads queue. We
+ * give out a token to the task, which it can use to resume the thread
+ * on return from the C function.
+ * ------------------------------------------------------------------------- */
+
+StgInt
+suspendThread( Capability *cap )
+{
+ nat tok;
+
+ ACQUIRE_LOCK(&sched_mutex);
+
+ IF_DEBUG(scheduler,
+ sched_belch("thread %d did a _ccall_gc", cap->rCurrentTSO->id));
+
+ threadPaused(cap->rCurrentTSO);
+ cap->rCurrentTSO->link = suspended_ccalling_threads;
+ suspended_ccalling_threads = cap->rCurrentTSO;
+
+ /* Use the thread ID as the token; it should be unique */
+ tok = cap->rCurrentTSO->id;
+
+#ifdef SMP
+ cap->link = free_capabilities;
+ free_capabilities = cap;
+ n_free_capabilities++;
+#endif
+
+ RELEASE_LOCK(&sched_mutex);
+ return tok;
+}
+
+Capability *
+resumeThread( StgInt tok )
+{
+ StgTSO *tso, **prev;
+ Capability *cap;
+
+ ACQUIRE_LOCK(&sched_mutex);
+
+ prev = &suspended_ccalling_threads;
+ for (tso = suspended_ccalling_threads;
+ tso != END_TSO_QUEUE;
+ prev = &tso->link, tso = tso->link) {
+ if (tso->id == (StgThreadID)tok) {
+ *prev = tso->link;
+ break;
+ }
+ }
+ if (tso == END_TSO_QUEUE) {
+ barf("resumeThread: thread not found");
+ }
+
+#ifdef SMP
+ while (free_capabilities == NULL) {
+ IF_DEBUG(scheduler, sched_belch("waiting to resume"));
+ pthread_cond_wait(&thread_ready_cond, &sched_mutex);
+ IF_DEBUG(scheduler, sched_belch("resuming thread %d", tso->id));
+ }
+ cap = free_capabilities;
+ free_capabilities = cap->link;
+ n_free_capabilities--;
+#else
+ cap = &MainRegTable;
+#endif
+
+ cap->rCurrentTSO = tso;
+
+ RELEASE_LOCK(&sched_mutex);
+ return cap;
+}
+
+
+/* ---------------------------------------------------------------------------
+ * Static functions
+ * ------------------------------------------------------------------------ */
+static void unblockThread(StgTSO *tso);
+
+/* ---------------------------------------------------------------------------
+ * Comparing Thread ids.
+ *
+ * This is used from STG land in the implementation of the
+ * instances of Eq/Ord for ThreadIds.
+ * ------------------------------------------------------------------------ */
+
+int cmp_thread(const StgTSO *tso1, const StgTSO *tso2)
+{
+ StgThreadID id1 = tso1->id;
+ StgThreadID id2 = tso2->id;
+
+ if (id1 < id2) return (-1);
+ if (id1 > id2) return 1;
+ return 0;
+}
+
+/* ---------------------------------------------------------------------------
+ Create a new thread.
+
+ The new thread starts with the given stack size. Before the
+ scheduler can run, however, this thread needs to have a closure
+ (and possibly some arguments) pushed on its stack. See
+ pushClosure() in Schedule.h.
+
+ createGenThread() and createIOThread() (in SchedAPI.h) are
+ convenient packaged versions of this function.
+
+ currently pri (priority) is only used in a GRAN setup -- HWL
+ ------------------------------------------------------------------------ */
+//@cindex createThread
+#if defined(GRAN)
+/* currently pri (priority) is only used in a GRAN setup -- HWL */
+StgTSO *
+createThread(nat stack_size, StgInt pri)
+{
+ return createThread_(stack_size, rtsFalse, pri);
+}
+
+static StgTSO *
+createThread_(nat size, rtsBool have_lock, StgInt pri)
+{
+#else
+StgTSO *
+createThread(nat stack_size)
+{
+ return createThread_(stack_size, rtsFalse);
+}
+
+static StgTSO *
+createThread_(nat size, rtsBool have_lock)
+{
+#endif
+
+ StgTSO *tso;
+ nat stack_size;
+
+ /* First check whether we should create a thread at all */
+#if defined(PAR)
+ /* check that no more than RtsFlags.ParFlags.maxThreads threads are created */
+ if (advisory_thread_count >= RtsFlags.ParFlags.maxThreads) {
+ threadsIgnored++;
+ belch("{createThread}Daq ghuH: refusing to create another thread; no more than %d threads allowed (currently %d)",
+ RtsFlags.ParFlags.maxThreads, advisory_thread_count);
+ return END_TSO_QUEUE;
+ }
+ threadsCreated++;
+#endif
+
+#if defined(GRAN)
+ ASSERT(!RtsFlags.GranFlags.Light || CurrentProc==0);
+#endif
+
+ // ToDo: check whether size = stack_size - TSO_STRUCT_SIZEW
+
+ /* catch ridiculously small stack sizes */
+ if (size < MIN_STACK_WORDS + TSO_STRUCT_SIZEW) {
+ size = MIN_STACK_WORDS + TSO_STRUCT_SIZEW;
+ }
+
+ stack_size = size - TSO_STRUCT_SIZEW;
+
+ tso = (StgTSO *)allocate(size);
+ TICK_ALLOC_TSO(size-TSO_STRUCT_SIZEW, 0);
+
+ SET_HDR(tso, &TSO_info, CCS_SYSTEM);
+#if defined(GRAN)
+ SET_GRAN_HDR(tso, ThisPE);
+#endif
+ tso->what_next = ThreadEnterGHC;
+
+ /* tso->id needs to be unique. For now we use a heavyweight mutex to
+ * protect the increment operation on next_thread_id.
+ * In future, we could use an atomic increment instead.
+ */
+ if (!have_lock) { ACQUIRE_LOCK(&sched_mutex); }
+ tso->id = next_thread_id++;
+ if (!have_lock) { RELEASE_LOCK(&sched_mutex); }
+
+ tso->why_blocked = NotBlocked;
+ tso->blocked_exceptions = NULL;
+
+ tso->stack_size = stack_size;
+ tso->max_stack_size = round_to_mblocks(RtsFlags.GcFlags.maxStkSize)
+ - TSO_STRUCT_SIZEW;
+ tso->sp = (P_)&(tso->stack) + stack_size;
+
+#ifdef PROFILING
+ tso->prof.CCCS = CCS_MAIN;
+#endif
+
+ /* put a stop frame on the stack */
+ tso->sp -= sizeofW(StgStopFrame);
+ SET_HDR((StgClosure*)tso->sp,(StgInfoTable *)&stg_stop_thread_info,CCS_SYSTEM);
+ tso->su = (StgUpdateFrame*)tso->sp;
+
+ // ToDo: check this
+#if defined(GRAN)
+ tso->link = END_TSO_QUEUE;
+ /* uses more flexible routine in GranSim */
+ insertThread(tso, CurrentProc);
+#else
+ /* In a non-GranSim setup the pushing of a TSO onto the runq is separated
+ * from its creation
+ */
+#endif
+
+#if defined(GRAN) || defined(PAR)
+ DumpGranEvent(GR_START,tso);
+#endif
+
+ /* Link the new thread on the global thread list.
+ */
+ tso->global_link = all_threads;
+ all_threads = tso;
+
+#if defined(GRAN)
+ tso->gran.pri = pri;
+# if defined(DEBUG)
+ tso->gran.magic = TSO_MAGIC; // debugging only
+# endif
+ tso->gran.sparkname = 0;
+ tso->gran.startedat = CURRENT_TIME;
+ tso->gran.exported = 0;
+ tso->gran.basicblocks = 0;
+ tso->gran.allocs = 0;
+ tso->gran.exectime = 0;
+ tso->gran.fetchtime = 0;
+ tso->gran.fetchcount = 0;
+ tso->gran.blocktime = 0;
+ tso->gran.blockcount = 0;
+ tso->gran.blockedat = 0;
+ tso->gran.globalsparks = 0;
+ tso->gran.localsparks = 0;
+ if (RtsFlags.GranFlags.Light)
+ tso->gran.clock = Now; /* local clock */
+ else
+ tso->gran.clock = 0;
+
+ IF_DEBUG(gran,printTSO(tso));
+#elif defined(PAR)
+# if defined(DEBUG)
+ tso->par.magic = TSO_MAGIC; // debugging only
+# endif
+ tso->par.sparkname = 0;
+ tso->par.startedat = CURRENT_TIME;
+ tso->par.exported = 0;
+ tso->par.basicblocks = 0;
+ tso->par.allocs = 0;
+ tso->par.exectime = 0;
+ tso->par.fetchtime = 0;
+ tso->par.fetchcount = 0;
+ tso->par.blocktime = 0;
+ tso->par.blockcount = 0;
+ tso->par.blockedat = 0;
+ tso->par.globalsparks = 0;
+ tso->par.localsparks = 0;
+#endif
+
+#if defined(GRAN)
+ globalGranStats.tot_threads_created++;
+ globalGranStats.threads_created_on_PE[CurrentProc]++;
+ globalGranStats.tot_sq_len += spark_queue_len(CurrentProc);
+ globalGranStats.tot_sq_probes++;
+#endif
+
+#if defined(GRAN)
+ IF_GRAN_DEBUG(pri,
+ belch("==__ schedule: Created TSO %d (%p);",
+ CurrentProc, tso, tso->id));
+#elif defined(PAR)
+ IF_PAR_DEBUG(verbose,
+ belch("==__ schedule: Created TSO %d (%p); %d threads active",
+ tso->id, tso, advisory_thread_count));
+#else
+ IF_DEBUG(scheduler,sched_belch("created thread %ld, stack size = %lx words",
+ tso->id, tso->stack_size));
+#endif
+ return tso;
+}
+
+/*
+ Turn a spark into a thread.
+ ToDo: fix for SMP (needs to acquire SCHED_MUTEX!)
+*/
+#if defined(PAR)
+//@cindex activateSpark
+StgTSO *
+activateSpark (rtsSpark spark)
+{
+ StgTSO *tso;
+
+ ASSERT(spark != (rtsSpark)NULL);
+ tso = createThread_(RtsFlags.GcFlags.initialStkSize, rtsTrue);
+ if (tso!=END_TSO_QUEUE) {
+ pushClosure(tso,spark);
+ PUSH_ON_RUN_QUEUE(tso);
+ advisory_thread_count++;
+
+ if (RtsFlags.ParFlags.ParStats.Full) {
+ //ASSERT(run_queue_hd == END_TSO_QUEUE); // I think ...
+ IF_PAR_DEBUG(verbose,
+ belch("==^^ activateSpark: turning spark of closure %p (%s) into a thread",
+ (StgClosure *)spark, info_type((StgClosure *)spark)));
+ }
+ } else {
+ barf("activateSpark: Cannot create TSO");
+ }
+ // ToDo: fwd info on local/global spark to thread -- HWL
+ // tso->gran.exported = spark->exported;
+ // tso->gran.locked = !spark->global;
+ // tso->gran.sparkname = spark->name;
+
+ return tso;
+}
+#endif
+
+/* ---------------------------------------------------------------------------
+ * scheduleThread()
+ *
+ * scheduleThread puts a thread on the head of the runnable queue.
+ * This will usually be done immediately after a thread is created.
+ * The caller of scheduleThread must create the thread using e.g.
+ * createThread and push an appropriate closure
+ * on this thread's stack before the scheduler is invoked.
+ * ------------------------------------------------------------------------ */
+
+void
+scheduleThread(StgTSO *tso)
+{
+ if (tso==END_TSO_QUEUE){
+ schedule();
+ return;
+ }
+
+ ACQUIRE_LOCK(&sched_mutex);
+
+ /* Put the new thread on the head of the runnable queue. The caller
+ * better push an appropriate closure on this thread's stack
+ * beforehand. In the SMP case, the thread may start running as
+ * soon as we release the scheduler lock below.
+ */
+ PUSH_ON_RUN_QUEUE(tso);
+ THREAD_RUNNABLE();
+
+#if 0
+ IF_DEBUG(scheduler,printTSO(tso));
+#endif
+ RELEASE_LOCK(&sched_mutex);
+}
+
+/* ---------------------------------------------------------------------------
+ * startTasks()
+ *
+ * Start up Posix threads to run each of the scheduler tasks.
+ * I believe the task ids are not needed in the system as defined.
+ * KH @ 25/10/99
+ * ------------------------------------------------------------------------ */
+
+#if defined(PAR) || defined(SMP)
+void *
+taskStart( void *arg STG_UNUSED )
+{
+ rts_evalNothing(NULL);
+}
+#endif
+
+/* ---------------------------------------------------------------------------
+ * initScheduler()
+ *
+ * Initialise the scheduler. This resets all the queues - if the
+ * queues contained any threads, they'll be garbage collected at the
+ * next pass.
+ *
+ * This now calls startTasks(), so should only be called once! KH @ 25/10/99
+ * ------------------------------------------------------------------------ */
+
+#ifdef SMP
+static void
+term_handler(int sig STG_UNUSED)
+{
+ stat_workerStop();
+ ACQUIRE_LOCK(&term_mutex);
+ await_death--;
+ RELEASE_LOCK(&term_mutex);
+ pthread_exit(NULL);
+}
+#endif
+
+//@cindex initScheduler
+void
+initScheduler(void)
+{
+#if defined(GRAN)
+ nat i;
+
+ for (i=0; i<=MAX_PROC; i++) {
+ run_queue_hds[i] = END_TSO_QUEUE;
+ run_queue_tls[i] = END_TSO_QUEUE;
+ blocked_queue_hds[i] = END_TSO_QUEUE;
+ blocked_queue_tls[i] = END_TSO_QUEUE;
+ ccalling_threadss[i] = END_TSO_QUEUE;
+ }
+#else
+ run_queue_hd = END_TSO_QUEUE;
+ run_queue_tl = END_TSO_QUEUE;
+ blocked_queue_hd = END_TSO_QUEUE;
+ blocked_queue_tl = END_TSO_QUEUE;
+#endif
+
+ suspended_ccalling_threads = END_TSO_QUEUE;
+
+ main_threads = NULL;
+ all_threads = END_TSO_QUEUE;
+
+ context_switch = 0;
+ interrupted = 0;
+
+ RtsFlags.ConcFlags.ctxtSwitchTicks =
+ RtsFlags.ConcFlags.ctxtSwitchTime / TICK_MILLISECS;
+
+#ifdef INTERPRETER
+ ecafList = END_ECAF_LIST;
+ clearECafTable();
+#endif
+
+ /* Install the SIGHUP handler */
+#ifdef SMP
+ {
+ struct sigaction action,oact;
+
+ action.sa_handler = term_handler;
+ sigemptyset(&action.sa_mask);
+ action.sa_flags = 0;
+ if (sigaction(SIGTERM, &action, &oact) != 0) {
+ barf("can't install TERM handler");
+ }
+ }
+#endif
+
+#ifdef SMP
+ /* Allocate N Capabilities */
+ {
+ nat i;
+ Capability *cap, *prev;
+ cap = NULL;
+ prev = NULL;
+ for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
+ cap = stgMallocBytes(sizeof(Capability), "initScheduler:capabilities");
+ cap->link = prev;
+ prev = cap;
+ }
+ free_capabilities = cap;
+ n_free_capabilities = RtsFlags.ParFlags.nNodes;
+ }
+ IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Allocated %d capabilities\n",
+ n_free_capabilities););
+#endif
+
+#if defined(SMP) || defined(PAR)
+ initSparkPools();
+#endif
+}
+
+#ifdef SMP
+void
+startTasks( void )
+{
+ nat i;
+ int r;
+ pthread_t tid;
+
+ /* make some space for saving all the thread ids */
+ task_ids = stgMallocBytes(RtsFlags.ParFlags.nNodes * sizeof(task_info),
+ "initScheduler:task_ids");
+
+ /* and create all the threads */
+ for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
+ r = pthread_create(&tid,NULL,taskStart,NULL);
+ if (r != 0) {
+ barf("startTasks: Can't create new Posix thread");
+ }
+ task_ids[i].id = tid;
+ task_ids[i].mut_time = 0.0;
+ task_ids[i].mut_etime = 0.0;
+ task_ids[i].gc_time = 0.0;
+ task_ids[i].gc_etime = 0.0;
+ task_ids[i].elapsedtimestart = elapsedtime();
+ IF_DEBUG(scheduler,fprintf(stderr,"scheduler: Started task: %ld\n",tid););
+ }
+}
+#endif
+
+void
+exitScheduler( void )
+{
+#ifdef SMP
+ nat i;
+
+ /* Don't want to use pthread_cancel, since we'd have to install
+ * these silly exception handlers (pthread_cleanup_{push,pop}) around
+ * all our locks.
+ */
+#if 0
+ /* Cancel all our tasks */
+ for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
+ pthread_cancel(task_ids[i].id);
+ }
+
+ /* Wait for all the tasks to terminate */
+ for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
+ IF_DEBUG(scheduler,fprintf(stderr,"scheduler: waiting for task %ld\n",
+ task_ids[i].id));
+ pthread_join(task_ids[i].id, NULL);
+ }
+#endif
+
+ /* Send 'em all a SIGHUP. That should shut 'em up.
+ */
+ await_death = RtsFlags.ParFlags.nNodes;
+ for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
+ pthread_kill(task_ids[i].id,SIGTERM);
+ }
+ while (await_death > 0) {
+ sched_yield();
+ }
+#endif
+}
+
+/* -----------------------------------------------------------------------------
+ Managing the per-task allocation areas.
+
+ Each capability comes with an allocation area. These are
+ fixed-length block lists into which allocation can be done.
+
+ ToDo: no support for two-space collection at the moment???
-------------------------------------------------------------------------- */
+/* -----------------------------------------------------------------------------
+ * waitThread is the external interface for running a new computation
+ * and waiting for the result.
+ *
+ * In the non-SMP case, we create a new main thread, push it on the
+ * main-thread stack, and invoke the scheduler to run it. The
+ * scheduler will return when the top main thread on the stack has
+ * completed or died, and fill in the necessary fields of the
+ * main_thread structure.
+ *
+ * In the SMP case, we create a main thread as before, but we then
+ * create a new condition variable and sleep on it. When our new
+ * main thread has completed, we'll be woken up and the status/result
+ * will be in the main_thread struct.
+ * -------------------------------------------------------------------------- */
+
+int
+howManyThreadsAvail ( void )
+{
+ int i = 0;
+ StgTSO* q;
+ for (q = run_queue_hd; q != END_TSO_QUEUE; q = q->link)
+ i++;
+ for (q = blocked_queue_hd; q != END_TSO_QUEUE; q = q->link)
+ i++;
+ return i;
+}
+
+void
+finishAllThreads ( void )
+{
+ do {
+ while (run_queue_hd != END_TSO_QUEUE) {
+ waitThread ( run_queue_hd, NULL );
+ }
+ while (blocked_queue_hd != END_TSO_QUEUE) {
+ waitThread ( blocked_queue_hd, NULL );
+ }
+ } while
+ (blocked_queue_hd != END_TSO_QUEUE ||
+ run_queue_hd != END_TSO_QUEUE);
+}
+
+SchedulerStatus
+waitThread(StgTSO *tso, /*out*/StgClosure **ret)
+{
+ StgMainThread *m;
+ SchedulerStatus stat;
+
+ ACQUIRE_LOCK(&sched_mutex);
+
+ m = stgMallocBytes(sizeof(StgMainThread), "waitThread");
+
+ m->tso = tso;
+ m->ret = ret;
+ m->stat = NoStatus;
+#ifdef SMP
+ pthread_cond_init(&m->wakeup, NULL);
+#endif
+
+ m->link = main_threads;
+ main_threads = m;
+
+ IF_DEBUG(scheduler, fprintf(stderr, "scheduler: new main thread (%d)\n",
+ m->tso->id));
+
+#ifdef SMP
+ do {
+ pthread_cond_wait(&m->wakeup, &sched_mutex);
+ } while (m->stat == NoStatus);
+#elif defined(GRAN)
+ /* GranSim specific init */
+ CurrentTSO = m->tso; // the TSO to run
+ procStatus[MainProc] = Busy; // status of main PE
+ CurrentProc = MainProc; // PE to run it on
+
+ schedule();
+#else
+ schedule();
+ ASSERT(m->stat != NoStatus);
+#endif
+
+ stat = m->stat;
+
+#ifdef SMP
+ pthread_cond_destroy(&m->wakeup);
+#endif
+
+ IF_DEBUG(scheduler, fprintf(stderr, "scheduler: main thread (%d) finished\n",
+ m->tso->id));
+ free(m);
+
+ RELEASE_LOCK(&sched_mutex);
+
+ return stat;
+}
+
+//@node Run queue code, Garbage Collextion Routines, Suspend and Resume, Main scheduling code
+//@subsection Run queue code
+
+#if 0
+/*
+ NB: In GranSim we have many run queues; run_queue_hd is actually a macro
+ unfolding to run_queue_hds[CurrentProc], thus CurrentProc is an
+ implicit global variable that has to be correct when calling these
+ fcts -- HWL
+*/
+
+/* Put the new thread on the head of the runnable queue.
+ * The caller of createThread better push an appropriate closure
+ * on this thread's stack before the scheduler is invoked.
+ */
+static /* inline */ void
+add_to_run_queue(tso)
+StgTSO* tso;
+{
+ ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
+ tso->link = run_queue_hd;
+ run_queue_hd = tso;
+ if (run_queue_tl == END_TSO_QUEUE) {
+ run_queue_tl = tso;
+ }
+}
+
+/* Put the new thread at the end of the runnable queue. */
+static /* inline */ void
+push_on_run_queue(tso)
+StgTSO* tso;
+{
+ ASSERT(get_itbl((StgClosure *)tso)->type == TSO);
+ ASSERT(run_queue_hd!=NULL && run_queue_tl!=NULL);
+ ASSERT(tso!=run_queue_hd && tso!=run_queue_tl);
+ if (run_queue_hd == END_TSO_QUEUE) {
+ run_queue_hd = tso;
+ } else {
+ run_queue_tl->link = tso;
+ }
+ run_queue_tl = tso;
+}
+
+/*
+ Should be inlined because it's used very often in schedule. The tso
+ argument is actually only needed in GranSim, where we want to have the
+ possibility to schedule *any* TSO on the run queue, irrespective of the
+ actual ordering. Therefore, if tso is not the nil TSO then we traverse
+ the run queue and dequeue the tso, adjusting the links in the queue.
+*/
+//@cindex take_off_run_queue
+static /* inline */ StgTSO*
+take_off_run_queue(StgTSO *tso) {
+ StgTSO *t, *prev;
+
+ /*
+ qetlaHbogh Qu' ngaSbogh ghomDaQ {tso} yIteq!
+
+ if tso is specified, unlink that tso from the run_queue (doesn't have
+ to be at the beginning of the queue); GranSim only
+ */
+ if (tso!=END_TSO_QUEUE) {
+ /* find tso in queue */
+ for (t=run_queue_hd, prev=END_TSO_QUEUE;
+ t!=END_TSO_QUEUE && t!=tso;
+ prev=t, t=t->link)
+ /* nothing */ ;
+ ASSERT(t==tso);
+ /* now actually dequeue the tso */
+ if (prev!=END_TSO_QUEUE) {
+ ASSERT(run_queue_hd!=t);
+ prev->link = t->link;
+ } else {
+ /* t is at beginning of thread queue */
+ ASSERT(run_queue_hd==t);
+ run_queue_hd = t->link;
+ }
+ /* t is at end of thread queue */
+ if (t->link==END_TSO_QUEUE) {
+ ASSERT(t==run_queue_tl);
+ run_queue_tl = prev;
+ } else {
+ ASSERT(run_queue_tl!=t);
+ }
+ t->link = END_TSO_QUEUE;
+ } else {
+ /* take tso from the beginning of the queue; std concurrent code */
+ t = run_queue_hd;
+ if (t != END_TSO_QUEUE) {
+ run_queue_hd = t->link;
+ t->link = END_TSO_QUEUE;
+ if (run_queue_hd == END_TSO_QUEUE) {
+ run_queue_tl = END_TSO_QUEUE;
+ }
+ }
+ }
+ return t;
+}
+
+#endif /* 0 */
+
+//@node Garbage Collextion Routines, Blocking Queue Routines, Run queue code, Main scheduling code
+//@subsection Garbage Collextion Routines
+
+/* ---------------------------------------------------------------------------
+ Where are the roots that we know about?
+
+ - all the threads on the runnable queue
+ - all the threads on the blocked queue
+ - all the thread currently executing a _ccall_GC
+ - all the "main threads"
+
+ ------------------------------------------------------------------------ */
+
+/* This has to be protected either by the scheduler monitor, or by the
+ garbage collection monitor (probably the latter).
+ KH @ 25/10/99
+*/
+
static void GetRoots(void)
{
- nat i;
+ StgMainThread *m;
+
+#if defined(GRAN)
+ {
+ nat i;
+ for (i=0; i<=RtsFlags.GranFlags.proc; i++) {
+ if ((run_queue_hds[i] != END_TSO_QUEUE) && ((run_queue_hds[i] != NULL)))
+ run_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_hds[i]);
+ if ((run_queue_tls[i] != END_TSO_QUEUE) && ((run_queue_tls[i] != NULL)))
+ run_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)run_queue_tls[i]);
+
+ if ((blocked_queue_hds[i] != END_TSO_QUEUE) && ((blocked_queue_hds[i] != NULL)))
+ blocked_queue_hds[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hds[i]);
+ if ((blocked_queue_tls[i] != END_TSO_QUEUE) && ((blocked_queue_tls[i] != NULL)))
+ blocked_queue_tls[i] = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tls[i]);
+ if ((ccalling_threadss[i] != END_TSO_QUEUE) && ((ccalling_threadss[i] != NULL)))
+ ccalling_threadss[i] = (StgTSO *)MarkRoot((StgClosure *)ccalling_threadss[i]);
+ }
+ }
- run_queue_hd = (StgTSO *)MarkRoot((StgClosure *)run_queue_hd);
- run_queue_tl = (StgTSO *)MarkRoot((StgClosure *)run_queue_tl);
+ markEventQueue();
- blocked_queue_hd = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hd);
- blocked_queue_tl = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tl);
+#else /* !GRAN */
+ if (run_queue_hd != END_TSO_QUEUE) {
+ ASSERT(run_queue_tl != END_TSO_QUEUE);
+ run_queue_hd = (StgTSO *)MarkRoot((StgClosure *)run_queue_hd);
+ run_queue_tl = (StgTSO *)MarkRoot((StgClosure *)run_queue_tl);
+ }
- ccalling_threads = (StgTSO *)MarkRoot((StgClosure *)ccalling_threads);
+ if (blocked_queue_hd != END_TSO_QUEUE) {
+ ASSERT(blocked_queue_tl != END_TSO_QUEUE);
+ blocked_queue_hd = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_hd);
+ blocked_queue_tl = (StgTSO *)MarkRoot((StgClosure *)blocked_queue_tl);
+ }
+#endif
- for (i = 0; i < next_main_thread; i++) {
- main_threads[i] = (StgTSO *)MarkRoot((StgClosure *)main_threads[i]);
+ for (m = main_threads; m != NULL; m = m->link) {
+ m->tso = (StgTSO *)MarkRoot((StgClosure *)m->tso);
}
+ if (suspended_ccalling_threads != END_TSO_QUEUE)
+ suspended_ccalling_threads =
+ (StgTSO *)MarkRoot((StgClosure *)suspended_ccalling_threads);
+
+#if defined(SMP) || defined(PAR) || defined(GRAN)
+ markSparkQueue();
+#endif
}
/* -----------------------------------------------------------------------------
It might be useful to provide an interface whereby the programmer
can specify more roots (ToDo).
+
+ This needs to be protected by the GC condition variable above. KH.
-------------------------------------------------------------------------- */
void (*extra_roots)(void);
void
performGC(void)
{
- GarbageCollect(GetRoots);
+ GarbageCollect(GetRoots,rtsFalse);
+}
+
+void
+performMajorGC(void)
+{
+ GarbageCollect(GetRoots,rtsTrue);
}
static void
{
extra_roots = get_roots;
- GarbageCollect(AllRoots);
+ GarbageCollect(AllRoots,rtsFalse);
}
/* -----------------------------------------------------------------------------
Stack overflow
- If the thread has reached its maximum stack size,
- then bomb out. Otherwise relocate the TSO into a larger chunk of
- memory and adjust its stack size appropriately.
+ If the thread has reached its maximum stack size, then raise the
+ StackOverflow exception in the offending thread. Otherwise
+ relocate the TSO into a larger chunk of memory and adjust its stack
+ size appropriately.
-------------------------------------------------------------------------- */
static StgTSO *
StgPtr new_sp;
StgTSO *dest;
- if (tso->stack_size >= tso->max_stack_size) {
-#if 0
- /* If we're debugging, just print out the top of the stack */
- printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
- tso->sp+64));
+ IF_DEBUG(sanity,checkTSO(tso));
+ if (tso->stack_size >= tso->max_stack_size) {
+
+ IF_DEBUG(gc,
+ belch("@@ threadStackOverflow of TSO %d (%p): stack too large (now %ld; max is %ld",
+ tso->id, tso, tso->stack_size, tso->max_stack_size);
+ /* If we're debugging, just print out the top of the stack */
+ printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
+ tso->sp+64)));
+
+#ifdef INTERPRETER
+ fprintf(stderr, "fatal: stack overflow in Hugs; aborting\n" );
+ exit(1);
+#else
+ /* Send this thread the StackOverflow exception */
+ raiseAsync(tso, (StgClosure *)stackOverflow_closure);
+#endif
+ return tso;
+ }
+
+ /* Try to double the current stack size. If that takes us over the
+ * maximum stack size for this thread, then use the maximum instead.
+ * Finally round up so the TSO ends up as a whole number of blocks.
+ */
+ new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
+ new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
+ TSO_STRUCT_SIZE)/sizeof(W_);
+ new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
+ new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
+
+ IF_DEBUG(scheduler, fprintf(stderr,"scheduler: increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
+
+ dest = (StgTSO *)allocate(new_tso_size);
+ TICK_ALLOC_TSO(new_tso_size-sizeofW(StgTSO),0);
+
+ /* copy the TSO block and the old stack into the new area */
+ memcpy(dest,tso,TSO_STRUCT_SIZE);
+ stack_words = tso->stack + tso->stack_size - tso->sp;
+ new_sp = (P_)dest + new_tso_size - stack_words;
+ memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
+
+ /* relocate the stack pointers... */
+ diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
+ dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
+ dest->sp = new_sp;
+ dest->stack_size = new_stack_size;
+
+ /* and relocate the update frame list */
+ relocate_TSO(tso, dest);
+
+ /* Mark the old TSO as relocated. We have to check for relocated
+ * TSOs in the garbage collector and any primops that deal with TSOs.
+ *
+ * It's important to set the sp and su values to just beyond the end
+ * of the stack, so we don't attempt to scavenge any part of the
+ * dead TSO's stack.
+ */
+ tso->what_next = ThreadRelocated;
+ tso->link = dest;
+ tso->sp = (P_)&(tso->stack[tso->stack_size]);
+ tso->su = (StgUpdateFrame *)tso->sp;
+ tso->why_blocked = NotBlocked;
+ dest->mut_link = NULL;
+
+ IF_PAR_DEBUG(verbose,
+ belch("@@ threadStackOverflow of TSO %d (now at %p): stack size increased to %ld",
+ tso->id, tso, tso->stack_size);
+ /* If we're debugging, just print out the top of the stack */
+ printStackChunk(tso->sp, stg_min(tso->stack+tso->stack_size,
+ tso->sp+64)));
+
+ IF_DEBUG(sanity,checkTSO(tso));
+#if 0
+ IF_DEBUG(scheduler,printTSO(dest));
+#endif
+
+ return dest;
+}
+
+//@node Blocking Queue Routines, Exception Handling Routines, Garbage Collextion Routines, Main scheduling code
+//@subsection Blocking Queue Routines
+
+/* ---------------------------------------------------------------------------
+ Wake up a queue that was blocked on some resource.
+ ------------------------------------------------------------------------ */
+
+/* ToDo: check push_on_run_queue vs. PUSH_ON_RUN_QUEUE */
+
+#if defined(GRAN)
+static inline void
+unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
+{
+}
+#elif defined(PAR)
+static inline void
+unblockCount ( StgBlockingQueueElement *bqe, StgClosure *node )
+{
+ /* write RESUME events to log file and
+ update blocked and fetch time (depending on type of the orig closure) */
+ if (RtsFlags.ParFlags.ParStats.Full) {
+ DumpRawGranEvent(CURRENT_PROC, CURRENT_PROC,
+ GR_RESUME, ((StgTSO *)bqe), ((StgTSO *)bqe)->block_info.closure,
+ 0, 0 /* spark_queue_len(ADVISORY_POOL) */);
+
+ switch (get_itbl(node)->type) {
+ case FETCH_ME_BQ:
+ ((StgTSO *)bqe)->par.fetchtime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
+ break;
+ case RBH:
+ case FETCH_ME:
+ case BLACKHOLE_BQ:
+ ((StgTSO *)bqe)->par.blocktime += CURRENT_TIME-((StgTSO *)bqe)->par.blockedat;
+ break;
+ default:
+ barf("{unblockOneLocked}Daq Qagh: unexpected closure in blocking queue");
+ }
+ }
+}
+#endif
+
+#if defined(GRAN)
+static StgBlockingQueueElement *
+unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
+{
+ StgTSO *tso;
+ PEs node_loc, tso_loc;
+
+ node_loc = where_is(node); // should be lifted out of loop
+ tso = (StgTSO *)bqe; // wastes an assignment to get the type right
+ tso_loc = where_is((StgClosure *)tso);
+ if (IS_LOCAL_TO(PROCS(node),tso_loc)) { // TSO is local
+ /* !fake_fetch => TSO is on CurrentProc is same as IS_LOCAL_TO */
+ ASSERT(CurrentProc!=node_loc || tso_loc==CurrentProc);
+ CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.lunblocktime;
+ // insertThread(tso, node_loc);
+ new_event(tso_loc, tso_loc, CurrentTime[CurrentProc],
+ ResumeThread,
+ tso, node, (rtsSpark*)NULL);
+ tso->link = END_TSO_QUEUE; // overwrite link just to be sure
+ // len_local++;
+ // len++;
+ } else { // TSO is remote (actually should be FMBQ)
+ CurrentTime[CurrentProc] += RtsFlags.GranFlags.Costs.mpacktime +
+ RtsFlags.GranFlags.Costs.gunblocktime +
+ RtsFlags.GranFlags.Costs.latency;
+ new_event(tso_loc, CurrentProc, CurrentTime[CurrentProc],
+ UnblockThread,
+ tso, node, (rtsSpark*)NULL);
+ tso->link = END_TSO_QUEUE; // overwrite link just to be sure
+ // len++;
+ }
+ /* the thread-queue-overhead is accounted for in either Resume or UnblockThread */
+ IF_GRAN_DEBUG(bq,
+ fprintf(stderr," %s TSO %d (%p) [PE %d] (block_info.closure=%p) (next=%p) ,",
+ (node_loc==tso_loc ? "Local" : "Global"),
+ tso->id, tso, CurrentProc, tso->block_info.closure, tso->link));
+ tso->block_info.closure = NULL;
+ IF_DEBUG(scheduler,belch("-- Waking up thread %ld (%p)",
+ tso->id, tso));
+}
+#elif defined(PAR)
+static StgBlockingQueueElement *
+unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node)
+{
+ StgBlockingQueueElement *next;
+
+ switch (get_itbl(bqe)->type) {
+ case TSO:
+ ASSERT(((StgTSO *)bqe)->why_blocked != NotBlocked);
+ /* if it's a TSO just push it onto the run_queue */
+ next = bqe->link;
+ // ((StgTSO *)bqe)->link = END_TSO_QUEUE; // debugging?
+ PUSH_ON_RUN_QUEUE((StgTSO *)bqe);
+ THREAD_RUNNABLE();
+ unblockCount(bqe, node);
+ /* reset blocking status after dumping event */
+ ((StgTSO *)bqe)->why_blocked = NotBlocked;
+ break;
+
+ case BLOCKED_FETCH:
+ /* if it's a BLOCKED_FETCH put it on the PendingFetches list */
+ next = bqe->link;
+ bqe->link = PendingFetches;
+ PendingFetches = bqe;
+ break;
+
+# if defined(DEBUG)
+ /* can ignore this case in a non-debugging setup;
+ see comments on RBHSave closures above */
+ case CONSTR:
+ /* check that the closure is an RBHSave closure */
+ ASSERT(get_itbl((StgClosure *)bqe) == &RBH_Save_0_info ||
+ get_itbl((StgClosure *)bqe) == &RBH_Save_1_info ||
+ get_itbl((StgClosure *)bqe) == &RBH_Save_2_info);
+ break;
+
+ default:
+ barf("{unblockOneLocked}Daq Qagh: Unexpected IP (%#lx; %s) in blocking queue at %#lx\n",
+ get_itbl((StgClosure *)bqe), info_type((StgClosure *)bqe),
+ (StgClosure *)bqe);
+# endif
+ }
+ // IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
+ return next;
+}
+
+#else /* !GRAN && !PAR */
+static StgTSO *
+unblockOneLocked(StgTSO *tso)
+{
+ StgTSO *next;
+
+ ASSERT(get_itbl(tso)->type == TSO);
+ ASSERT(tso->why_blocked != NotBlocked);
+ tso->why_blocked = NotBlocked;
+ next = tso->link;
+ PUSH_ON_RUN_QUEUE(tso);
+ THREAD_RUNNABLE();
+ IF_DEBUG(scheduler,sched_belch("waking up thread %ld", tso->id));
+ return next;
+}
#endif
-#ifdef INTERPRETER
- fprintf(stderr, "fatal: stack overflow in Hugs; aborting\n" );
- exit(1);
+
+#if defined(GRAN) || defined(PAR)
+inline StgBlockingQueueElement *
+unblockOne(StgBlockingQueueElement *bqe, StgClosure *node)
+{
+ ACQUIRE_LOCK(&sched_mutex);
+ bqe = unblockOneLocked(bqe, node);
+ RELEASE_LOCK(&sched_mutex);
+ return bqe;
+}
#else
- /* Send this thread the StackOverflow exception */
- raiseAsync(tso, (StgClosure *)&stackOverflow_closure);
+inline StgTSO *
+unblockOne(StgTSO *tso)
+{
+ ACQUIRE_LOCK(&sched_mutex);
+ tso = unblockOneLocked(tso);
+ RELEASE_LOCK(&sched_mutex);
+ return tso;
+}
#endif
- return tso;
+
+#if defined(GRAN)
+void
+awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
+{
+ StgBlockingQueueElement *bqe;
+ PEs node_loc;
+ nat len = 0;
+
+ IF_GRAN_DEBUG(bq,
+ belch("## AwBQ for node %p on PE %d @ %ld by TSO %d (%p): ", \
+ node, CurrentProc, CurrentTime[CurrentProc],
+ CurrentTSO->id, CurrentTSO));
+
+ node_loc = where_is(node);
+
+ ASSERT(get_itbl(q)->type == TSO || // q is either a TSO or an RBHSave
+ get_itbl(q)->type == CONSTR); // closure (type constructor)
+ ASSERT(is_unique(node));
+
+ /* FAKE FETCH: magically copy the node to the tso's proc;
+ no Fetch necessary because in reality the node should not have been
+ moved to the other PE in the first place
+ */
+ if (CurrentProc!=node_loc) {
+ IF_GRAN_DEBUG(bq,
+ belch("## node %p is on PE %d but CurrentProc is %d (TSO %d); assuming fake fetch and adjusting bitmask (old: %#x)",
+ node, node_loc, CurrentProc, CurrentTSO->id,
+ // CurrentTSO, where_is(CurrentTSO),
+ node->header.gran.procs));
+ node->header.gran.procs = (node->header.gran.procs) | PE_NUMBER(CurrentProc);
+ IF_GRAN_DEBUG(bq,
+ belch("## new bitmask of node %p is %#x",
+ node, node->header.gran.procs));
+ if (RtsFlags.GranFlags.GranSimStats.Global) {
+ globalGranStats.tot_fake_fetches++;
+ }
}
- /* Try to double the current stack size. If that takes us over the
- * maximum stack size for this thread, then use the maximum instead.
- * Finally round up so the TSO ends up as a whole number of blocks.
- */
- new_stack_size = stg_min(tso->stack_size * 2, tso->max_stack_size);
- new_tso_size = (nat)BLOCK_ROUND_UP(new_stack_size * sizeof(W_) +
- TSO_STRUCT_SIZE)/sizeof(W_);
- new_tso_size = round_to_mblocks(new_tso_size); /* Be MBLOCK-friendly */
- new_stack_size = new_tso_size - TSO_STRUCT_SIZEW;
+ bqe = q;
+ // ToDo: check: ASSERT(CurrentProc==node_loc);
+ while (get_itbl(bqe)->type==TSO) { // q != END_TSO_QUEUE) {
+ //next = bqe->link;
+ /*
+ bqe points to the current element in the queue
+ next points to the next element in the queue
+ */
+ //tso = (StgTSO *)bqe; // wastes an assignment to get the type right
+ //tso_loc = where_is(tso);
+ len++;
+ bqe = unblockOneLocked(bqe, node);
+ }
- IF_DEBUG(scheduler, fprintf(stderr,"increasing stack size from %d words to %d.\n", tso->stack_size, new_stack_size));
+ /* if this is the BQ of an RBH, we have to put back the info ripped out of
+ the closure to make room for the anchor of the BQ */
+ if (bqe!=END_BQ_QUEUE) {
+ ASSERT(get_itbl(node)->type == RBH && get_itbl(bqe)->type == CONSTR);
+ /*
+ ASSERT((info_ptr==&RBH_Save_0_info) ||
+ (info_ptr==&RBH_Save_1_info) ||
+ (info_ptr==&RBH_Save_2_info));
+ */
+ /* cf. convertToRBH in RBH.c for writing the RBHSave closure */
+ ((StgRBH *)node)->blocking_queue = (StgBlockingQueueElement *)((StgRBHSave *)bqe)->payload[0];
+ ((StgRBH *)node)->mut_link = (StgMutClosure *)((StgRBHSave *)bqe)->payload[1];
+
+ IF_GRAN_DEBUG(bq,
+ belch("## Filled in RBH_Save for %p (%s) at end of AwBQ",
+ node, info_type(node)));
+ }
- dest = (StgTSO *)allocate(new_tso_size);
- TICK_ALLOC_TSO(new_tso_size-sizeofW(StgTSO),0);
+ /* statistics gathering */
+ if (RtsFlags.GranFlags.GranSimStats.Global) {
+ // globalGranStats.tot_bq_processing_time += bq_processing_time;
+ globalGranStats.tot_bq_len += len; // total length of all bqs awakened
+ // globalGranStats.tot_bq_len_local += len_local; // same for local TSOs only
+ globalGranStats.tot_awbq++; // total no. of bqs awakened
+ }
+ IF_GRAN_DEBUG(bq,
+ fprintf(stderr,"## BQ Stats of %p: [%d entries] %s\n",
+ node, len, (bqe!=END_BQ_QUEUE) ? "RBH" : ""));
+}
+#elif defined(PAR)
+void
+awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node)
+{
+ StgBlockingQueueElement *bqe, *next;
- /* copy the TSO block and the old stack into the new area */
- memcpy(dest,tso,TSO_STRUCT_SIZE);
- stack_words = tso->stack + tso->stack_size - tso->sp;
- new_sp = (P_)dest + new_tso_size - stack_words;
- memcpy(new_sp, tso->sp, stack_words * sizeof(W_));
+ ACQUIRE_LOCK(&sched_mutex);
- /* relocate the stack pointers... */
- diff = (P_)new_sp - (P_)tso->sp; /* In *words* */
- dest->su = (StgUpdateFrame *) ((P_)dest->su + diff);
- dest->sp = new_sp;
- dest->splim = (P_)dest->splim + (nat)((P_)dest - (P_)tso);
- dest->stack_size = new_stack_size;
-
- /* and relocate the update frame list */
- relocate_TSO(tso, dest);
+ IF_PAR_DEBUG(verbose,
+ belch("## AwBQ for node %p on [%x]: ",
+ node, mytid));
- /* Mark the old one as dead so we don't try to scavenge it during
- * garbage collection (the TSO will likely be on a mutables list in
- * some generation, but it'll get collected soon enough). It's
- * important to set the sp and su values to just beyond the end of
- * the stack, so we don't attempt to scavenge any part of the dead
- * TSO's stack.
- */
- tso->whatNext = ThreadKilled;
- tso->sp = (P_)&(tso->stack[tso->stack_size]);
- tso->su = (StgUpdateFrame *)tso->sp;
- tso->blocked_on = NULL;
- dest->mut_link = NULL;
+ ASSERT(get_itbl(q)->type == TSO ||
+ get_itbl(q)->type == BLOCKED_FETCH ||
+ get_itbl(q)->type == CONSTR);
- IF_DEBUG(sanity,checkTSO(tso));
-#if 0
- IF_DEBUG(scheduler,printTSO(dest));
-#endif
- if (tso == MainTSO) { /* hack */
- MainTSO = dest;
+ bqe = q;
+ while (get_itbl(bqe)->type==TSO ||
+ get_itbl(bqe)->type==BLOCKED_FETCH) {
+ bqe = unblockOneLocked(bqe, node);
}
- return dest;
+ RELEASE_LOCK(&sched_mutex);
}
-/* -----------------------------------------------------------------------------
- Wake up a queue that was blocked on some resource (usually a
- computation in progress).
- -------------------------------------------------------------------------- */
-
-void awaken_blocked_queue(StgTSO *q)
+#else /* !GRAN && !PAR */
+void
+awakenBlockedQueue(StgTSO *tso)
{
- StgTSO *tso;
-
- while (q != END_TSO_QUEUE) {
- ASSERT(get_itbl(q)->type == TSO);
- tso = q;
- q = tso->link;
- PUSH_ON_RUN_QUEUE(tso);
- tso->blocked_on = NULL;
- IF_DEBUG(scheduler,belch("Waking up thread %ld", tso->id));
+ ACQUIRE_LOCK(&sched_mutex);
+ while (tso != END_TSO_QUEUE) {
+ tso = unblockOneLocked(tso);
}
+ RELEASE_LOCK(&sched_mutex);
}
+#endif
-/* -----------------------------------------------------------------------------
+//@node Exception Handling Routines, Debugging Routines, Blocking Queue Routines, Main scheduling code
+//@subsection Exception Handling Routines
+
+/* ---------------------------------------------------------------------------
Interrupt execution
- usually called inside a signal handler so it mustn't do anything fancy.
- -------------------------------------------------------------------------- */
+ ------------------------------------------------------------------------ */
void
interruptStgRts(void)
This is for use when we raise an exception in another thread, which
may be blocked.
+ This has nothing to do with the UnblockThread event in GranSim. -- HWL
-------------------------------------------------------------------------- */
+#if defined(GRAN) || defined(PAR)
+/*
+ NB: only the type of the blocking queue is different in GranSim and GUM
+ the operations on the queue-elements are the same
+ long live polymorphism!
+*/
static void
unblockThread(StgTSO *tso)
{
- StgTSO *t, **last;
+ StgBlockingQueueElement *t, **last;
+
+ ACQUIRE_LOCK(&sched_mutex);
+ switch (tso->why_blocked) {
- if (tso->blocked_on == NULL) {
+ case NotBlocked:
return; /* not blocked */
+
+ case BlockedOnMVar:
+ ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
+ {
+ StgBlockingQueueElement *last_tso = END_BQ_QUEUE;
+ StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
+
+ last = (StgBlockingQueueElement **)&mvar->head;
+ for (t = (StgBlockingQueueElement *)mvar->head;
+ t != END_BQ_QUEUE;
+ last = &t->link, last_tso = t, t = t->link) {
+ if (t == (StgBlockingQueueElement *)tso) {
+ *last = (StgBlockingQueueElement *)tso->link;
+ if (mvar->tail == tso) {
+ mvar->tail = (StgTSO *)last_tso;
+ }
+ goto done;
+ }
+ }
+ barf("unblockThread (MVAR): TSO not found");
+ }
+
+ case BlockedOnBlackHole:
+ ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
+ {
+ StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
+
+ last = &bq->blocking_queue;
+ for (t = bq->blocking_queue;
+ t != END_BQ_QUEUE;
+ last = &t->link, t = t->link) {
+ if (t == (StgBlockingQueueElement *)tso) {
+ *last = (StgBlockingQueueElement *)tso->link;
+ goto done;
+ }
+ }
+ barf("unblockThread (BLACKHOLE): TSO not found");
+ }
+
+ case BlockedOnException:
+ {
+ StgTSO *target = tso->block_info.tso;
+
+ ASSERT(get_itbl(target)->type == TSO);
+ ASSERT(target->blocked_exceptions != NULL);
+
+ last = (StgBlockingQueueElement **)&target->blocked_exceptions;
+ for (t = (StgBlockingQueueElement *)target->blocked_exceptions;
+ t != END_BQ_QUEUE;
+ last = &t->link, t = t->link) {
+ ASSERT(get_itbl(t)->type == TSO);
+ if (t == (StgBlockingQueueElement *)tso) {
+ *last = (StgBlockingQueueElement *)tso->link;
+ goto done;
+ }
+ }
+ barf("unblockThread (Exception): TSO not found");
+ }
+
+ case BlockedOnDelay:
+ case BlockedOnRead:
+ case BlockedOnWrite:
+ {
+ StgBlockingQueueElement *prev = NULL;
+ for (t = (StgBlockingQueueElement *)blocked_queue_hd; t != END_BQ_QUEUE;
+ prev = t, t = t->link) {
+ if (t == (StgBlockingQueueElement *)tso) {
+ if (prev == NULL) {
+ blocked_queue_hd = (StgTSO *)t->link;
+ if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
+ blocked_queue_tl = END_TSO_QUEUE;
+ }
+ } else {
+ prev->link = t->link;
+ if ((StgBlockingQueueElement *)blocked_queue_tl == t) {
+ blocked_queue_tl = (StgTSO *)prev;
+ }
+ }
+ goto done;
+ }
+ }
+ barf("unblockThread (I/O): TSO not found");
+ }
+
+ default:
+ barf("unblockThread");
}
- switch (get_itbl(tso->blocked_on)->type) {
+ done:
+ tso->link = END_TSO_QUEUE;
+ tso->why_blocked = NotBlocked;
+ tso->block_info.closure = NULL;
+ PUSH_ON_RUN_QUEUE(tso);
+ RELEASE_LOCK(&sched_mutex);
+}
+#else
+static void
+unblockThread(StgTSO *tso)
+{
+ StgTSO *t, **last;
+
+ ACQUIRE_LOCK(&sched_mutex);
+ switch (tso->why_blocked) {
- case MVAR:
+ case NotBlocked:
+ return; /* not blocked */
+
+ case BlockedOnMVar:
+ ASSERT(get_itbl(tso->block_info.closure)->type == MVAR);
{
StgTSO *last_tso = END_TSO_QUEUE;
- StgMVar *mvar = (StgMVar *)(tso->blocked_on);
+ StgMVar *mvar = (StgMVar *)(tso->block_info.closure);
last = &mvar->head;
for (t = mvar->head; t != END_TSO_QUEUE;
barf("unblockThread (MVAR): TSO not found");
}
- case BLACKHOLE_BQ:
+ case BlockedOnBlackHole:
+ ASSERT(get_itbl(tso->block_info.closure)->type == BLACKHOLE_BQ);
{
- StgBlockingQueue *bq = (StgBlockingQueue *)(tso->blocked_on);
+ StgBlockingQueue *bq = (StgBlockingQueue *)(tso->block_info.closure);
last = &bq->blocking_queue;
for (t = bq->blocking_queue; t != END_TSO_QUEUE;
barf("unblockThread (BLACKHOLE): TSO not found");
}
+ case BlockedOnException:
+ {
+ StgTSO *target = tso->block_info.tso;
+
+ ASSERT(get_itbl(target)->type == TSO);
+ ASSERT(target->blocked_exceptions != NULL);
+
+ last = &target->blocked_exceptions;
+ for (t = target->blocked_exceptions; t != END_TSO_QUEUE;
+ last = &t->link, t = t->link) {
+ ASSERT(get_itbl(t)->type == TSO);
+ if (t == tso) {
+ *last = tso->link;
+ goto done;
+ }
+ }
+ barf("unblockThread (Exception): TSO not found");
+ }
+
+ case BlockedOnDelay:
+ case BlockedOnRead:
+ case BlockedOnWrite:
+ {
+ StgTSO *prev = NULL;
+ for (t = blocked_queue_hd; t != END_TSO_QUEUE;
+ prev = t, t = t->link) {
+ if (t == tso) {
+ if (prev == NULL) {
+ blocked_queue_hd = t->link;
+ if (blocked_queue_tl == t) {
+ blocked_queue_tl = END_TSO_QUEUE;
+ }
+ } else {
+ prev->link = t->link;
+ if (blocked_queue_tl == t) {
+ blocked_queue_tl = prev;
+ }
+ }
+ goto done;
+ }
+ }
+ barf("unblockThread (I/O): TSO not found");
+ }
+
default:
barf("unblockThread");
}
done:
tso->link = END_TSO_QUEUE;
- tso->blocked_on = NULL;
+ tso->why_blocked = NotBlocked;
+ tso->block_info.closure = NULL;
PUSH_ON_RUN_QUEUE(tso);
+ RELEASE_LOCK(&sched_mutex);
}
+#endif
/* -----------------------------------------------------------------------------
* raiseAsync()
StgPtr sp = tso->sp;
/* Thread already dead? */
- if (tso->whatNext == ThreadComplete || tso->whatNext == ThreadKilled) {
+ if (tso->what_next == ThreadComplete || tso->what_next == ThreadKilled) {
return;
}
- IF_DEBUG(scheduler, belch("Raising exception in thread %ld.", tso->id));
+ IF_DEBUG(scheduler, sched_belch("raising exception in thread %ld.", tso->id));
/* Remove it from any blocking queues */
unblockThread(tso);
StgAP_UPD * ap;
/* If we find a CATCH_FRAME, and we've got an exception to raise,
- * then build PAP(handler,exception), and leave it on top of
- * the stack ready to enter.
+ * then build PAP(handler,exception,realworld#), and leave it on
+ * top of the stack ready to enter.
*/
if (get_itbl(su)->type == CATCH_FRAME && exception != NULL) {
StgCatchFrame *cf = (StgCatchFrame *)su;
/* we've got an exception to raise, so let's pass it to the
* handler in this frame.
*/
- ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 1);
- TICK_ALLOC_UPD_PAP(2,0);
+ ap = (StgAP_UPD *)allocate(sizeofW(StgPAP) + 2);
+ TICK_ALLOC_UPD_PAP(3,0);
SET_HDR(ap,&PAP_info,cf->header.prof.ccs);
- ap->n_args = 1;
- ap->fun = cf->handler;
- ap->payload[0] = (P_)exception;
+ ap->n_args = 2;
+ ap->fun = cf->handler; /* :: Exception -> IO a */
+ ap->payload[0] = exception;
+ ap->payload[1] = ARG_TAG(0); /* realworld token */
- /* sp currently points to the word above the CATCH_FRAME on the
- * stack. Replace the CATCH_FRAME with a pointer to the new handler
- * application.
+ /* throw away the stack from Sp up to and including the
+ * CATCH_FRAME.
*/
- sp += sizeofW(StgCatchFrame);
- sp[0] = (W_)ap;
+ sp = (P_)su + sizeofW(StgCatchFrame) - 1;
tso->su = cf->link;
+
+ /* Restore the blocked/unblocked state for asynchronous exceptions
+ * at the CATCH_FRAME.
+ *
+ * If exceptions were unblocked at the catch, arrange that they
+ * are unblocked again after executing the handler by pushing an
+ * unblockAsyncExceptions_ret stack frame.
+ */
+ if (!cf->exceptions_blocked) {
+ *(sp--) = (W_)&unblockAsyncExceptionszh_ret_info;
+ }
+
+ /* Ensure that async exceptions are blocked when running the handler.
+ */
+ if (tso->blocked_exceptions == NULL) {
+ tso->blocked_exceptions = END_TSO_QUEUE;
+ }
+
+ /* Put the newly-built PAP on top of the stack, ready to execute
+ * when the thread restarts.
+ */
+ sp[0] = (W_)ap;
tso->sp = sp;
- tso->whatNext = ThreadEnterGHC;
+ tso->what_next = ThreadEnterGHC;
+ IF_DEBUG(sanity, checkTSO(tso));
return;
}
ap->fun = (StgClosure *)sp[0];
sp++;
for(i=0; i < (nat)words; ++i) {
- ap->payload[i] = (P_)*sp++;
+ ap->payload[i] = (StgClosure *)*sp++;
}
switch (get_itbl(su)->type) {
TICK_ALLOC_UP_THK(words+1,0);
IF_DEBUG(scheduler,
- fprintf(stderr, "Updating ");
+ fprintf(stderr, "scheduler: Updating ");
printPtr((P_)su->updatee);
fprintf(stderr, " with ");
printObj((StgClosure *)ap);
* this will also wake up any threads currently
* waiting on the result.
*/
- UPD_IND(su->updatee,ap); /* revert the black hole */
+ UPD_IND_NOLOCK(su->updatee,ap); /* revert the black hole */
su = su->link;
sp += sizeofW(StgUpdateFrame) -1;
sp[0] = (W_)ap; /* push onto stack */
o->payload[1] = cf->handler;
IF_DEBUG(scheduler,
- fprintf(stderr, "Built ");
+ fprintf(stderr, "scheduler: Built ");
printObj((StgClosure *)o);
);
o = (StgClosure *)allocate(sizeofW(StgClosure)+1);
TICK_ALLOC_SE_THK(1,0);
SET_HDR(o,&seq_info,su->header.prof.ccs /* ToDo */);
- payloadCPtr(o,0) = (StgClosure *)ap;
+ o->payload[0] = (StgClosure *)ap;
IF_DEBUG(scheduler,
- fprintf(stderr, "Built ");
+ fprintf(stderr, "scheduler: Built ");
printObj((StgClosure *)o);
);
/* We've stripped the entire stack, the thread is now dead. */
sp += sizeofW(StgStopFrame) - 1;
sp[0] = (W_)exception; /* save the exception */
- tso->whatNext = ThreadKilled;
+ tso->what_next = ThreadKilled;
tso->su = (StgUpdateFrame *)(sp+1);
tso->sp = sp;
return;
}
barf("raiseAsync");
}
+
+/* -----------------------------------------------------------------------------
+ resurrectThreads is called after garbage collection on the list of
+ threads found to be garbage. Each of these threads will be woken
+ up and sent a signal: BlockedOnDeadMVar if the thread was blocked
+ on an MVar, or NonTermination if the thread was blocked on a Black
+ Hole.
+ -------------------------------------------------------------------------- */
+
+void
+resurrectThreads( StgTSO *threads )
+{
+ StgTSO *tso, *next;
+
+ for (tso = threads; tso != END_TSO_QUEUE; tso = next) {
+ next = tso->global_link;
+ tso->global_link = all_threads;
+ all_threads = tso;
+ IF_DEBUG(scheduler, sched_belch("resurrecting thread %d", tso->id));
+
+ switch (tso->why_blocked) {
+ case BlockedOnMVar:
+ case BlockedOnException:
+ raiseAsync(tso,(StgClosure *)BlockedOnDeadMVar_closure);
+ break;
+ case BlockedOnBlackHole:
+ raiseAsync(tso,(StgClosure *)NonTermination_closure);
+ break;
+ case NotBlocked:
+ /* This might happen if the thread was blocked on a black hole
+ * belonging to a thread that we've just woken up (raiseAsync
+ * can wake up threads, remember...).
+ */
+ continue;
+ default:
+ barf("resurrectThreads: thread blocked in a strange way");
+ }
+ }
+}
+
+/* -----------------------------------------------------------------------------
+ * Blackhole detection: if we reach a deadlock, test whether any
+ * threads are blocked on themselves. Any threads which are found to
+ * be self-blocked get sent a NonTermination exception.
+ *
+ * This is only done in a deadlock situation in order to avoid
+ * performance overhead in the normal case.
+ * -------------------------------------------------------------------------- */
+
+static void
+detectBlackHoles( void )
+{
+ StgTSO *t = all_threads;
+ StgUpdateFrame *frame;
+ StgClosure *blocked_on;
+
+ for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
+
+ if (t->why_blocked != BlockedOnBlackHole) {
+ continue;
+ }
+
+ blocked_on = t->block_info.closure;
+
+ for (frame = t->su; ; frame = frame->link) {
+ switch (get_itbl(frame)->type) {
+
+ case UPDATE_FRAME:
+ if (frame->updatee == blocked_on) {
+ /* We are blocking on one of our own computations, so
+ * send this thread the NonTermination exception.
+ */
+ IF_DEBUG(scheduler,
+ sched_belch("thread %d is blocked on itself", t->id));
+ raiseAsync(t, (StgClosure *)NonTermination_closure);
+ goto done;
+ }
+ else {
+ continue;
+ }
+
+ case CATCH_FRAME:
+ case SEQ_FRAME:
+ continue;
+
+ case STOP_FRAME:
+ break;
+ }
+ break;
+ }
+
+ done:
+ }
+}
+
+//@node Debugging Routines, Index, Exception Handling Routines, Main scheduling code
+//@subsection Debugging Routines
+
+/* -----------------------------------------------------------------------------
+ Debugging: why is a thread blocked
+ -------------------------------------------------------------------------- */
+
+#ifdef DEBUG
+
+void
+printThreadBlockage(StgTSO *tso)
+{
+ switch (tso->why_blocked) {
+ case BlockedOnRead:
+ fprintf(stderr,"blocked on read from fd %d", tso->block_info.fd);
+ break;
+ case BlockedOnWrite:
+ fprintf(stderr,"blocked on write to fd %d", tso->block_info.fd);
+ break;
+ case BlockedOnDelay:
+#if defined(HAVE_SETITIMER) || defined(mingw32_TARGET_OS)
+ fprintf(stderr,"blocked on delay of %d ms", tso->block_info.delay);
+#else
+ fprintf(stderr,"blocked on delay of %d ms",
+ tso->block_info.target - getourtimeofday());
+#endif
+ break;
+ case BlockedOnMVar:
+ fprintf(stderr,"blocked on an MVar");
+ break;
+ case BlockedOnException:
+ fprintf(stderr,"blocked on delivering an exception to thread %d",
+ tso->block_info.tso->id);
+ break;
+ case BlockedOnBlackHole:
+ fprintf(stderr,"blocked on a black hole");
+ break;
+ case NotBlocked:
+ fprintf(stderr,"not blocked");
+ break;
+#if defined(PAR)
+ case BlockedOnGA:
+ fprintf(stderr,"blocked on global address; local FM_BQ is %p (%s)",
+ tso->block_info.closure, info_type(tso->block_info.closure));
+ break;
+ case BlockedOnGA_NoSend:
+ fprintf(stderr,"blocked on global address (no send); local FM_BQ is %p (%s)",
+ tso->block_info.closure, info_type(tso->block_info.closure));
+ break;
+#endif
+ default:
+ barf("printThreadBlockage: strange tso->why_blocked: %d for TSO %d (%d)",
+ tso->why_blocked, tso->id, tso);
+ }
+}
+
+void
+printThreadStatus(StgTSO *tso)
+{
+ switch (tso->what_next) {
+ case ThreadKilled:
+ fprintf(stderr,"has been killed");
+ break;
+ case ThreadComplete:
+ fprintf(stderr,"has completed");
+ break;
+ default:
+ printThreadBlockage(tso);
+ }
+}
+
+void
+printAllThreads(void)
+{
+ StgTSO *t;
+
+ sched_belch("all threads:");
+ for (t = all_threads; t != END_TSO_QUEUE; t = t->global_link) {
+ fprintf(stderr, "\tthread %d is ", t->id);
+ printThreadStatus(t);
+ fprintf(stderr,"\n");
+ }
+}
+
+/*
+ Print a whole blocking queue attached to node (debugging only).
+*/
+//@cindex print_bq
+# if defined(PAR)
+void
+print_bq (StgClosure *node)
+{
+ StgBlockingQueueElement *bqe;
+ StgTSO *tso;
+ rtsBool end;
+
+ fprintf(stderr,"## BQ of closure %p (%s): ",
+ node, info_type(node));
+
+ /* should cover all closures that may have a blocking queue */
+ ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
+ get_itbl(node)->type == FETCH_ME_BQ ||
+ get_itbl(node)->type == RBH);
+
+ ASSERT(node!=(StgClosure*)NULL); // sanity check
+ /*
+ NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
+ */
+ for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
+ !end; // iterate until bqe points to a CONSTR
+ end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
+ ASSERT(bqe != END_BQ_QUEUE); // sanity check
+ ASSERT(bqe != (StgTSO*)NULL); // sanity check
+ /* types of closures that may appear in a blocking queue */
+ ASSERT(get_itbl(bqe)->type == TSO ||
+ get_itbl(bqe)->type == BLOCKED_FETCH ||
+ get_itbl(bqe)->type == CONSTR);
+ /* only BQs of an RBH end with an RBH_Save closure */
+ ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
+
+ switch (get_itbl(bqe)->type) {
+ case TSO:
+ fprintf(stderr," TSO %d (%x),",
+ ((StgTSO *)bqe)->id, ((StgTSO *)bqe));
+ break;
+ case BLOCKED_FETCH:
+ fprintf(stderr," BF (node=%p, ga=((%x, %d, %x)),",
+ ((StgBlockedFetch *)bqe)->node,
+ ((StgBlockedFetch *)bqe)->ga.payload.gc.gtid,
+ ((StgBlockedFetch *)bqe)->ga.payload.gc.slot,
+ ((StgBlockedFetch *)bqe)->ga.weight);
+ break;
+ case CONSTR:
+ fprintf(stderr," %s (IP %p),",
+ (get_itbl(bqe) == &RBH_Save_0_info ? "RBH_Save_0" :
+ get_itbl(bqe) == &RBH_Save_1_info ? "RBH_Save_1" :
+ get_itbl(bqe) == &RBH_Save_2_info ? "RBH_Save_2" :
+ "RBH_Save_?"), get_itbl(bqe));
+ break;
+ default:
+ barf("Unexpected closure type %s in blocking queue of %p (%s)",
+ info_type(bqe), node, info_type(node));
+ break;
+ }
+ } /* for */
+ fputc('\n', stderr);
+}
+# elif defined(GRAN)
+void
+print_bq (StgClosure *node)
+{
+ StgBlockingQueueElement *bqe;
+ PEs node_loc, tso_loc;
+ rtsBool end;
+
+ /* should cover all closures that may have a blocking queue */
+ ASSERT(get_itbl(node)->type == BLACKHOLE_BQ ||
+ get_itbl(node)->type == FETCH_ME_BQ ||
+ get_itbl(node)->type == RBH);
+
+ ASSERT(node!=(StgClosure*)NULL); // sanity check
+ node_loc = where_is(node);
+
+ fprintf(stderr,"## BQ of closure %p (%s) on [PE %d]: ",
+ node, info_type(node), node_loc);
+
+ /*
+ NB: In a parallel setup a BQ of an RBH must end with an RBH_Save closure;
+ */
+ for (bqe = ((StgBlockingQueue*)node)->blocking_queue, end = (bqe==END_BQ_QUEUE);
+ !end; // iterate until bqe points to a CONSTR
+ end = (get_itbl(bqe)->type == CONSTR) || (bqe->link==END_BQ_QUEUE), bqe = end ? END_BQ_QUEUE : bqe->link) {
+ ASSERT(bqe != END_BQ_QUEUE); // sanity check
+ ASSERT(bqe != (StgBlockingQueueElement *)NULL); // sanity check
+ /* types of closures that may appear in a blocking queue */
+ ASSERT(get_itbl(bqe)->type == TSO ||
+ get_itbl(bqe)->type == CONSTR);
+ /* only BQs of an RBH end with an RBH_Save closure */
+ ASSERT(get_itbl(bqe)->type != CONSTR || get_itbl(node)->type == RBH);
+
+ tso_loc = where_is((StgClosure *)bqe);
+ switch (get_itbl(bqe)->type) {
+ case TSO:
+ fprintf(stderr," TSO %d (%p) on [PE %d],",
+ ((StgTSO *)bqe)->id, (StgTSO *)bqe, tso_loc);
+ break;
+ case CONSTR:
+ fprintf(stderr," %s (IP %p),",
+ (get_itbl(bqe) == &RBH_Save_0_info ? "RBH_Save_0" :
+ get_itbl(bqe) == &RBH_Save_1_info ? "RBH_Save_1" :
+ get_itbl(bqe) == &RBH_Save_2_info ? "RBH_Save_2" :
+ "RBH_Save_?"), get_itbl(bqe));
+ break;
+ default:
+ barf("Unexpected closure type %s in blocking queue of %p (%s)",
+ info_type((StgClosure *)bqe), node, info_type(node));
+ break;
+ }
+ } /* for */
+ fputc('\n', stderr);
+}
+#else
+/*
+ Nice and easy: only TSOs on the blocking queue
+*/
+void
+print_bq (StgClosure *node)
+{
+ StgTSO *tso;
+
+ ASSERT(node!=(StgClosure*)NULL); // sanity check
+ for (tso = ((StgBlockingQueue*)node)->blocking_queue;
+ tso != END_TSO_QUEUE;
+ tso=tso->link) {
+ ASSERT(tso!=NULL && tso!=END_TSO_QUEUE); // sanity check
+ ASSERT(get_itbl(tso)->type == TSO); // guess what, sanity check
+ fprintf(stderr," TSO %d (%p),", tso->id, tso);
+ }
+ fputc('\n', stderr);
+}
+# endif
+
+#if defined(PAR)
+static nat
+run_queue_len(void)
+{
+ nat i;
+ StgTSO *tso;
+
+ for (i=0, tso=run_queue_hd;
+ tso != END_TSO_QUEUE;
+ i++, tso=tso->link)
+ /* nothing */
+
+ return i;
+}
+#endif
+
+static void
+sched_belch(char *s, ...)
+{
+ va_list ap;
+ va_start(ap,s);
+#ifdef SMP
+ fprintf(stderr, "scheduler (task %ld): ", pthread_self());
+#else
+ fprintf(stderr, "scheduler: ");
+#endif
+ vfprintf(stderr, s, ap);
+ fprintf(stderr, "\n");
+}
+
+#endif /* DEBUG */
+
+
+//@node Index, , Debugging Routines, Main scheduling code
+//@subsection Index
+
+//@index
+//* MainRegTable:: @cindex\s-+MainRegTable
+//* StgMainThread:: @cindex\s-+StgMainThread
+//* awaken_blocked_queue:: @cindex\s-+awaken_blocked_queue
+//* blocked_queue_hd:: @cindex\s-+blocked_queue_hd
+//* blocked_queue_tl:: @cindex\s-+blocked_queue_tl
+//* context_switch:: @cindex\s-+context_switch
+//* createThread:: @cindex\s-+createThread
+//* free_capabilities:: @cindex\s-+free_capabilities
+//* gc_pending_cond:: @cindex\s-+gc_pending_cond
+//* initScheduler:: @cindex\s-+initScheduler
+//* interrupted:: @cindex\s-+interrupted
+//* n_free_capabilities:: @cindex\s-+n_free_capabilities
+//* next_thread_id:: @cindex\s-+next_thread_id
+//* print_bq:: @cindex\s-+print_bq
+//* run_queue_hd:: @cindex\s-+run_queue_hd
+//* run_queue_tl:: @cindex\s-+run_queue_tl
+//* sched_mutex:: @cindex\s-+sched_mutex
+//* schedule:: @cindex\s-+schedule
+//* take_off_run_queue:: @cindex\s-+take_off_run_queue
+//* task_ids:: @cindex\s-+task_ids
+//* term_mutex:: @cindex\s-+term_mutex
+//* thread_ready_cond:: @cindex\s-+thread_ready_cond
+//@end index