1 /* -----------------------------------------------------------------------------
2 * $Id: Schedule.h,v 1.44 2004/02/26 16:14:21 simonmar Exp $
4 * (c) The GHC Team 1998-1999
6 * Prototypes for functions in Schedule.c
7 * (RTS internal scheduler interface)
9 * -------------------------------------------------------------------------*/
11 #ifndef __SCHEDULE_H__
12 #define __SCHEDULE_H__
13 #include "OSThreads.h"
15 /* initScheduler(), exitScheduler(), startTasks()
17 * Called from STG : no
18 * Locks assumed : none
20 extern void initScheduler ( void );
21 extern void exitScheduler ( void );
23 /* awakenBlockedQueue()
25 * Takes a pointer to the beginning of a blocked TSO queue, and
26 * wakes up the entire queue.
28 * Called from STG : yes
29 * Locks assumed : none
32 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
34 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
36 void awakenBlockedQueue(StgTSO *tso);
37 #if defined(RTS_SUPPORTS_THREADS)
38 void awakenBlockedQueueNoLock(StgTSO *tso);
44 * Takes a pointer to the beginning of a blocked TSO queue, and
45 * removes the first thread, placing it on the runnable queue.
47 * Called from STG : yes
48 * Locks assumed : none
50 #if defined(GRAN) || defined(PAR)
51 StgBlockingQueueElement *unblockOne(StgBlockingQueueElement *bqe, StgClosure *node);
53 StgTSO *unblockOne(StgTSO *tso);
58 * Raises an exception asynchronously in the specified thread.
60 * Called from STG : yes
61 * Locks assumed : none
63 void raiseAsync(StgTSO *tso, StgClosure *exception);
64 void raiseAsyncWithLock(StgTSO *tso, StgClosure *exception);
66 /* awaitEvent(rtsBool wait)
68 * Checks for blocked threads that need to be woken.
70 * Called from STG : NO
71 * Locks assumed : sched_mutex
73 void awaitEvent(rtsBool wait); /* In Select.c */
75 /* wakeUpSleepingThreads(nat ticks)
77 * Wakes up any sleeping threads whose timers have expired.
79 * Called from STG : NO
80 * Locks assumed : sched_mutex
82 rtsBool wakeUpSleepingThreads(nat); /* In Select.c */
84 /* wakeBlockedWorkerThread()
86 * If a worker thread is currently blocked in awaitEvent(), interrupt it.
88 * Called from STG : NO
89 * Locks assumed : sched_mutex
91 void wakeBlockedWorkerThread(void); /* In Select.c */
93 /* resetWorkerWakeupPipeAfterFork()
95 * Notify Select.c that a fork() has occured
97 * Called from STG : NO
98 * Locks assumed : don't care, but must be called right after fork()
100 void resetWorkerWakeupPipeAfterFork(void); /* In Select.c */
102 /* GetRoots(evac_fn f)
104 * Call f() for each root known to the scheduler.
106 * Called from STG : NO
107 * Locks assumed : ????
109 void GetRoots(evac_fn);
111 // ToDo: check whether all fcts below are used in the SMP version, too
113 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
114 void unlink_from_bq(StgTSO* tso, StgClosure* node);
115 void initThread(StgTSO *tso, nat stack_size, StgInt pri);
117 nat run_queue_len(void);
118 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
119 void initThread(StgTSO *tso, nat stack_size);
121 char *info_type(StgClosure *closure); // dummy
122 char *info_type_by_ip(StgInfoTable *ip); // dummy
123 void awaken_blocked_queue(StgTSO *q);
124 void initThread(StgTSO *tso, nat stack_size);
127 /* Context switch flag.
128 * Locks required : sched_mutex
130 extern nat context_switch;
131 extern rtsBool interrupted;
134 extern nat timestamp;
137 * Locks required : sched_mutex
139 * In GranSim we have one run/blocked_queue per PE.
142 // run_queue_hds defined in GranSim.h
144 extern StgTSO *run_queue_hd, *run_queue_tl;
145 extern StgTSO *blocked_queue_hd, *blocked_queue_tl;
146 extern StgTSO *sleeping_queue;
148 /* Linked list of all threads. */
149 extern StgTSO *all_threads;
151 #if defined(RTS_SUPPORTS_THREADS)
152 /* Schedule.c has detailed info on what these do */
153 extern Mutex sched_mutex;
154 extern Condition returning_worker_cond;
155 extern nat rts_n_waiting_workers;
156 extern nat rts_n_waiting_tasks;
159 StgBool rtsSupportsBoundThreads(void);
160 StgBool isThreadBound(StgTSO *tso);
161 StgInt forkProcess(HsStablePtr *entry);
163 extern SchedulerStatus rts_mainLazyIO(HaskellObj p, /*out*/HaskellObj *ret);
166 /* Called by shutdown_handler(). */
167 void interruptStgRts ( void );
169 void raiseAsync(StgTSO *tso, StgClosure *exception);
170 nat run_queue_len(void);
172 void resurrectThreads( StgTSO * );
176 * These are the threads which clients have requested that we run.
178 * In a 'threaded' build, each of these corresponds to one bound thread.
179 * The pointer to the StgMainThread is passed as a parameter to schedule;
180 * this invocation of schedule will always pass this main thread's
181 * bound_thread_cond to waitForkWorkCapability; OS-thread-switching
182 * takes place using passCapability.
184 * In non-threaded builds, clients are strictly nested: the first client calls
185 * into the RTS, which might call out again to C with a _ccall_GC, and
186 * eventually re-enter the RTS.
188 * This is non-abstract at the moment because the garbage collector
189 * treats pointers to TSOs from the main thread list as "weak" - these
190 * pointers won't prevent a thread from receiving a BlockedOnDeadMVar
193 * Main threads information is kept in a linked list:
195 typedef struct StgMainThread_ {
197 SchedulerStatus stat;
199 #if defined(RTS_SUPPORTS_THREADS)
200 #if defined(THREADED_RTS)
201 Condition bound_thread_cond;
206 struct StgMainThread_ *link;
209 /* Main thread queue.
210 * Locks required: sched_mutex.
212 extern StgMainThread *main_threads;
214 void printAllThreads(void);
215 #ifdef COMPILING_SCHEDULER
216 static void printThreadBlockage(StgTSO *tso);
217 static void printThreadStatus(StgTSO *tso);
222 void print_bq (StgClosure *node);
225 void print_bqe (StgBlockingQueueElement *bqe);
228 void labelThread(StgPtr tso, char *label);
230 /* -----------------------------------------------------------------------------
231 * Some convenient macros...
234 /* END_TSO_QUEUE and friends now defined in includes/StgMiscClosures.h */
236 /* Add a thread to the end of the run queue.
237 * NOTE: tso->link should be END_TSO_QUEUE before calling this macro.
239 #define APPEND_TO_RUN_QUEUE(tso) \
240 ASSERT(tso->link == END_TSO_QUEUE); \
241 if (run_queue_hd == END_TSO_QUEUE) { \
242 run_queue_hd = tso; \
244 run_queue_tl->link = tso; \
248 /* Push a thread on the beginning of the run queue. Used for
249 * newly awakened threads, so they get run as soon as possible.
251 #define PUSH_ON_RUN_QUEUE(tso) \
252 tso->link = run_queue_hd; \
253 run_queue_hd = tso; \
254 if (run_queue_tl == END_TSO_QUEUE) { \
255 run_queue_tl = tso; \
258 /* Pop the first thread off the runnable queue.
260 #define POP_RUN_QUEUE(pt) \
261 do { StgTSO *__tmp_t = run_queue_hd; \
262 if (__tmp_t != END_TSO_QUEUE) { \
263 run_queue_hd = __tmp_t->link; \
264 __tmp_t->link = END_TSO_QUEUE; \
265 if (run_queue_hd == END_TSO_QUEUE) { \
266 run_queue_tl = END_TSO_QUEUE; \
272 /* Add a thread to the end of the blocked queue.
274 #define APPEND_TO_BLOCKED_QUEUE(tso) \
275 ASSERT(tso->link == END_TSO_QUEUE); \
276 if (blocked_queue_hd == END_TSO_QUEUE) { \
277 blocked_queue_hd = tso; \
279 blocked_queue_tl->link = tso; \
281 blocked_queue_tl = tso;
283 /* Signal that a runnable thread has become available, in
284 * case there are any waiting tasks to execute it.
286 #if defined(RTS_SUPPORTS_THREADS)
287 #define THREAD_RUNNABLE() \
288 wakeBlockedWorkerThread(); \
291 #define THREAD_RUNNABLE() /* nothing */
294 /* Check whether various thread queues are empty
296 #define EMPTY_QUEUE(q) (q == END_TSO_QUEUE)
298 #define EMPTY_RUN_QUEUE() (EMPTY_QUEUE(run_queue_hd))
299 #define EMPTY_BLOCKED_QUEUE() (EMPTY_QUEUE(blocked_queue_hd))
300 #define EMPTY_SLEEPING_QUEUE() (EMPTY_QUEUE(sleeping_queue))
302 #define EMPTY_THREAD_QUEUES() (EMPTY_RUN_QUEUE() && \
303 EMPTY_BLOCKED_QUEUE() && \
304 EMPTY_SLEEPING_QUEUE())
306 #if defined(RTS_SUPPORTS_THREADS)
307 /* If no task is waiting for a capability,
308 * and if there is work to be done
309 * or if we need to wait for IO or delay requests,
310 * spawn a new worker thread.
313 startSchedulerTaskIfNecessary(void);
317 extern void sched_belch(char *s, ...);
320 #endif /* __SCHEDULE_H__ */