1 /* -----------------------------------------------------------------------------
2 * $Id: Schedule.h,v 1.41 2003/10/01 10:57:43 wolfgang 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 thread_ready_cond;
155 extern Condition returning_worker_cond;
156 extern nat rts_n_waiting_workers;
157 extern nat rts_n_waiting_tasks;
160 StgBool rtsSupportsBoundThreads(void);
161 StgBool isThreadBound(StgTSO *tso);
162 StgInt forkProcess(HsStablePtr *entry);
164 extern SchedulerStatus rts_mainLazyIO(HaskellObj p, /*out*/HaskellObj *ret);
167 /* Called by shutdown_handler(). */
168 void interruptStgRts ( void );
170 void raiseAsync(StgTSO *tso, StgClosure *exception);
171 nat run_queue_len(void);
173 void resurrectThreads( StgTSO * );
177 * These are the threads which clients have requested that we run.
179 * In a 'threaded' build, each of these corresponds to one bound thread.
180 * The pointer to the StgMainThread is passed as a parameter to schedule;
181 * this invocation of schedule will always pass this main thread's
182 * bound_thread_cond to waitForkWorkCapability; OS-thread-switching
183 * takes place using passCapability.
185 * In non-threaded builds, clients are strictly nested: the first client calls
186 * into the RTS, which might call out again to C with a _ccall_GC, and
187 * eventually re-enter the RTS.
189 * This is non-abstract at the moment because the garbage collector
190 * treats pointers to TSOs from the main thread list as "weak" - these
191 * pointers won't prevent a thread from receiving a BlockedOnDeadMVar
194 * Main threads information is kept in a linked list:
196 typedef struct StgMainThread_ {
198 SchedulerStatus stat;
200 #if defined(RTS_SUPPORTS_THREADS)
201 #if defined(THREADED_RTS)
202 Condition bound_thread_cond;
207 struct StgMainThread_ *link;
210 /* Main thread queue.
211 * Locks required: sched_mutex.
213 extern StgMainThread *main_threads;
215 void printAllThreads(void);
216 #ifdef COMPILING_SCHEDULER
217 static void printThreadBlockage(StgTSO *tso);
218 static void printThreadStatus(StgTSO *tso);
223 void print_bq (StgClosure *node);
226 void print_bqe (StgBlockingQueueElement *bqe);
229 void labelThread(StgPtr tso, char *label);
231 /* -----------------------------------------------------------------------------
232 * Some convenient macros...
235 /* END_TSO_QUEUE and friends now defined in includes/StgMiscClosures.h */
237 /* Add a thread to the end of the run queue.
238 * NOTE: tso->link should be END_TSO_QUEUE before calling this macro.
240 #define APPEND_TO_RUN_QUEUE(tso) \
241 ASSERT(tso->link == END_TSO_QUEUE); \
242 if (run_queue_hd == END_TSO_QUEUE) { \
243 run_queue_hd = tso; \
245 run_queue_tl->link = tso; \
249 /* Push a thread on the beginning of the run queue. Used for
250 * newly awakened threads, so they get run as soon as possible.
252 #define PUSH_ON_RUN_QUEUE(tso) \
253 tso->link = run_queue_hd; \
254 run_queue_hd = tso; \
255 if (run_queue_tl == END_TSO_QUEUE) { \
256 run_queue_tl = tso; \
259 /* Pop the first thread off the runnable queue.
261 #define POP_RUN_QUEUE() \
262 ({ StgTSO *t = run_queue_hd; \
263 if (t != END_TSO_QUEUE) { \
264 run_queue_hd = t->link; \
265 t->link = END_TSO_QUEUE; \
266 if (run_queue_hd == END_TSO_QUEUE) { \
267 run_queue_tl = END_TSO_QUEUE; \
273 /* Add a thread to the end of the blocked queue.
275 #define APPEND_TO_BLOCKED_QUEUE(tso) \
276 ASSERT(tso->link == END_TSO_QUEUE); \
277 if (blocked_queue_hd == END_TSO_QUEUE) { \
278 blocked_queue_hd = tso; \
280 blocked_queue_tl->link = tso; \
282 blocked_queue_tl = tso;
284 /* Signal that a runnable thread has become available, in
285 * case there are any waiting tasks to execute it.
287 #if defined(RTS_SUPPORTS_THREADS)
288 #define THREAD_RUNNABLE() \
289 wakeBlockedWorkerThread(); \
292 #define THREAD_RUNNABLE() /* nothing */
295 /* Check whether various thread queues are empty
297 #define EMPTY_QUEUE(q) (q == END_TSO_QUEUE)
299 #define EMPTY_RUN_QUEUE() (EMPTY_QUEUE(run_queue_hd))
300 #define EMPTY_BLOCKED_QUEUE() (EMPTY_QUEUE(blocked_queue_hd))
301 #define EMPTY_SLEEPING_QUEUE() (EMPTY_QUEUE(sleeping_queue))
303 #define EMPTY_THREAD_QUEUES() (EMPTY_RUN_QUEUE() && \
304 EMPTY_BLOCKED_QUEUE() && \
305 EMPTY_SLEEPING_QUEUE())
307 #if defined(RTS_SUPPORTS_THREADS)
308 /* If no task is waiting for a capability,
309 * and if there is work to be done
310 * or if we need to wait for IO or delay requests,
311 * spawn a new worker thread.
314 startSchedulerTaskIfNecessary(void);
317 #endif /* __SCHEDULE_H__ */