1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team 1998-1999
5 * Prototypes for functions in Schedule.c
6 * (RTS internal scheduler interface)
8 * -------------------------------------------------------------------------*/
10 #ifndef __SCHEDULE_H__
11 #define __SCHEDULE_H__
12 #include "OSThreads.h"
14 /* initScheduler(), exitScheduler(), startTasks()
16 * Called from STG : no
17 * Locks assumed : none
19 extern void initScheduler ( void );
20 extern void exitScheduler ( void );
22 /* awakenBlockedQueue()
24 * Takes a pointer to the beginning of a blocked TSO queue, and
25 * wakes up the entire queue.
27 * Called from STG : yes
28 * Locks assumed : none
31 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
33 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
35 void awakenBlockedQueue (StgTSO *tso);
36 void awakenBlockedQueueNoLock (StgTSO *tso);
41 * Takes a pointer to the beginning of a blocked TSO queue, and
42 * removes the first thread, placing it on the runnable queue.
44 * Called from STG : yes
45 * Locks assumed : none
47 #if defined(GRAN) || defined(PAR)
48 StgBlockingQueueElement *unblockOne(StgBlockingQueueElement *bqe, StgClosure *node);
49 StgBlockingQueueElement *unblockOneLocked(StgBlockingQueueElement *bqe, StgClosure *node);
51 StgTSO *unblockOne(StgTSO *tso);
52 StgTSO *unblockOneLocked(StgTSO *tso);
57 * Raises an exception asynchronously in the specified thread.
59 * Called from STG : yes
60 * Locks assumed : none
62 void raiseAsync(StgTSO *tso, StgClosure *exception);
63 void raiseAsyncWithLock(StgTSO *tso, StgClosure *exception);
65 /* raiseExceptionHelper */
66 StgWord raiseExceptionHelper (StgTSO *tso, StgClosure *exception);
68 /* findRetryFrameHelper */
69 StgWord findRetryFrameHelper (StgTSO *tso);
71 /* awaitEvent(rtsBool wait)
73 * Checks for blocked threads that need to be woken.
75 * Called from STG : NO
76 * Locks assumed : sched_mutex
78 void awaitEvent(rtsBool wait); /* In Select.c */
80 /* wakeUpSleepingThreads(nat ticks)
82 * Wakes up any sleeping threads whose timers have expired.
84 * Called from STG : NO
85 * Locks assumed : sched_mutex
87 rtsBool wakeUpSleepingThreads(lnat); /* In Select.c */
89 /* wakeBlockedWorkerThread()
91 * If a worker thread is currently blocked in awaitEvent(), interrupt it.
93 * Called from STG : NO
94 * Locks assumed : sched_mutex
96 void wakeBlockedWorkerThread(void); /* In Select.c */
98 /* resetWorkerWakeupPipeAfterFork()
100 * Notify Select.c that a fork() has occured
102 * Called from STG : NO
103 * Locks assumed : don't care, but must be called right after fork()
105 void resetWorkerWakeupPipeAfterFork(void); /* In Select.c */
107 /* GetRoots(evac_fn f)
109 * Call f() for each root known to the scheduler.
111 * Called from STG : NO
112 * Locks assumed : ????
114 void GetRoots(evac_fn);
116 // ToDo: check whether all fcts below are used in the SMP version, too
118 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
119 void unlink_from_bq(StgTSO* tso, StgClosure* node);
120 void initThread(StgTSO *tso, nat stack_size, StgInt pri);
122 nat run_queue_len(void);
123 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
124 void initThread(StgTSO *tso, nat stack_size);
126 char *info_type(StgClosure *closure); // dummy
127 char *info_type_by_ip(StgInfoTable *ip); // dummy
128 void awaken_blocked_queue(StgTSO *q);
129 void initThread(StgTSO *tso, nat stack_size);
132 /* Context switch flag.
133 * Locks required : sched_mutex
135 extern int RTS_VAR(context_switch);
136 extern rtsBool RTS_VAR(interrupted);
139 * flag that tracks whether we have done any execution in this time slice.
141 #define ACTIVITY_YES 0 /* there has been activity in the current slice */
142 #define ACTIVITY_MAYBE_NO 1 /* no activity in the current slice */
143 #define ACTIVITY_INACTIVE 2 /* a complete slice has passed with no activity */
144 #define ACTIVITY_DONE_GC 3 /* like 2, but we've done a GC too */
145 extern nat recent_activity;
148 extern lnat RTS_VAR(timestamp);
151 * Locks required : sched_mutex
153 * In GranSim we have one run/blocked_queue per PE.
156 // run_queue_hds defined in GranSim.h
158 extern StgTSO *RTS_VAR(run_queue_hd), *RTS_VAR(run_queue_tl);
159 extern StgTSO *RTS_VAR(blocked_queue_hd), *RTS_VAR(blocked_queue_tl);
160 extern StgTSO *RTS_VAR(blackhole_queue);
161 extern StgTSO *RTS_VAR(sleeping_queue);
163 /* Linked list of all threads. */
164 extern StgTSO *RTS_VAR(all_threads);
166 /* Set to rtsTrue if there are threads on the blackhole_queue, and
167 * it is possible that one or more of them may be available to run.
168 * This flag is set to rtsFalse after we've checked the queue, and
169 * set to rtsTrue just before we run some Haskell code. It is used
170 * to decide whether we should yield the Capability or not.
172 extern rtsBool blackholes_need_checking;
174 #if defined(RTS_SUPPORTS_THREADS)
175 /* Schedule.c has detailed info on what these do */
176 extern Mutex RTS_VAR(sched_mutex);
177 extern Condition RTS_VAR(returning_worker_cond);
178 extern nat RTS_VAR(rts_n_waiting_workers);
179 extern nat RTS_VAR(rts_n_waiting_tasks);
182 StgBool isThreadBound(StgTSO *tso);
184 extern SchedulerStatus rts_mainLazyIO(HaskellObj p, /*out*/HaskellObj *ret);
187 /* Called by shutdown_handler(). */
188 void interruptStgRts ( void );
190 void raiseAsync(StgTSO *tso, StgClosure *exception);
191 nat run_queue_len(void);
193 void resurrectThreads( StgTSO * );
197 * These are the threads which clients have requested that we run.
199 * In a 'threaded' build, each of these corresponds to one bound thread.
200 * The pointer to the StgMainThread is passed as a parameter to schedule;
201 * this invocation of schedule will always pass this main thread's
202 * bound_thread_cond to waitForkWorkCapability; OS-thread-switching
203 * takes place using passCapability.
205 * In non-threaded builds, clients are strictly nested: the first client calls
206 * into the RTS, which might call out again to C with a _ccall_GC, and
207 * eventually re-enter the RTS.
209 * This is non-abstract at the moment because the garbage collector
210 * treats pointers to TSOs from the main thread list as "weak" - these
211 * pointers won't prevent a thread from receiving a BlockedOnDeadMVar
214 * Main threads information is kept in a linked list:
216 typedef struct StgMainThread_ {
218 SchedulerStatus stat;
220 #if defined(RTS_SUPPORTS_THREADS)
221 Condition bound_thread_cond;
223 struct StgMainThread_ *prev;
224 struct StgMainThread_ *link;
227 /* Main thread queue.
228 * Locks required: sched_mutex.
230 extern StgMainThread *main_threads;
232 void printAllThreads(void);
233 #ifdef COMPILING_SCHEDULER
234 static void printThreadBlockage(StgTSO *tso);
235 static void printThreadStatus(StgTSO *tso);
240 void print_bq (StgClosure *node);
243 void print_bqe (StgBlockingQueueElement *bqe);
246 void labelThread(StgPtr tso, char *label);
248 /* -----------------------------------------------------------------------------
249 * Some convenient macros...
252 /* END_TSO_QUEUE and friends now defined in includes/StgMiscClosures.h */
254 /* Add a thread to the end of the run queue.
255 * NOTE: tso->link should be END_TSO_QUEUE before calling this macro.
257 #define APPEND_TO_RUN_QUEUE(tso) \
258 ASSERT(tso->link == END_TSO_QUEUE); \
259 if (run_queue_hd == END_TSO_QUEUE) { \
260 run_queue_hd = tso; \
262 run_queue_tl->link = tso; \
266 /* Push a thread on the beginning of the run queue. Used for
267 * newly awakened threads, so they get run as soon as possible.
269 #define PUSH_ON_RUN_QUEUE(tso) \
270 tso->link = run_queue_hd; \
271 run_queue_hd = tso; \
272 if (run_queue_tl == END_TSO_QUEUE) { \
273 run_queue_tl = tso; \
276 /* Pop the first thread off the runnable queue.
278 #define POP_RUN_QUEUE(pt) \
279 do { StgTSO *__tmp_t = run_queue_hd; \
280 if (__tmp_t != END_TSO_QUEUE) { \
281 run_queue_hd = __tmp_t->link; \
282 __tmp_t->link = END_TSO_QUEUE; \
283 if (run_queue_hd == END_TSO_QUEUE) { \
284 run_queue_tl = END_TSO_QUEUE; \
290 /* Add a thread to the end of the blocked queue.
292 #define APPEND_TO_BLOCKED_QUEUE(tso) \
293 ASSERT(tso->link == END_TSO_QUEUE); \
294 if (blocked_queue_hd == END_TSO_QUEUE) { \
295 blocked_queue_hd = tso; \
297 blocked_queue_tl->link = tso; \
299 blocked_queue_tl = tso;
301 /* Check whether various thread queues are empty
303 #define EMPTY_QUEUE(q) (q == END_TSO_QUEUE)
305 #define EMPTY_RUN_QUEUE() (EMPTY_QUEUE(run_queue_hd))
306 #define EMPTY_BLOCKED_QUEUE() (EMPTY_QUEUE(blocked_queue_hd))
307 #define EMPTY_SLEEPING_QUEUE() (EMPTY_QUEUE(sleeping_queue))
309 #define EMPTY_THREAD_QUEUES() (EMPTY_RUN_QUEUE() && \
310 EMPTY_BLOCKED_QUEUE() && \
311 EMPTY_SLEEPING_QUEUE())
313 #if defined(RTS_SUPPORTS_THREADS)
314 /* If no task is waiting for a capability,
315 * and if there is work to be done
316 * or if we need to wait for IO or delay requests,
317 * spawn a new worker thread.
320 startSchedulerTaskIfNecessary(void);
324 extern void sched_belch(char *s, ...)
325 GNU_ATTRIBUTE(format (printf, 1, 2));
328 #endif /* __SCHEDULE_H__ */