1 /* -----------------------------------------------------------------------------
3 * (c) The GHC Team 1998-2005
5 * Prototypes for functions in Schedule.c
6 * (RTS internal scheduler interface)
8 * -------------------------------------------------------------------------*/
13 #include "OSThreads.h"
14 #include "Capability.h"
16 /* initScheduler(), exitScheduler()
17 * Called from STG : no
18 * Locks assumed : none
20 void initScheduler (void);
21 void exitScheduler (rtsBool wait_foreign);
22 void freeScheduler (void);
24 // Place a new thread on the run queue of the current Capability
25 void scheduleThread (Capability *cap, StgTSO *tso);
27 // Place a new thread on the run queue of a specified Capability
28 // (cap is the currently owned Capability, cpu is the number of
29 // the desired Capability).
30 void scheduleThreadOn(Capability *cap, StgWord cpu, StgTSO *tso);
32 /* awakenBlockedQueue()
34 * Takes a pointer to the beginning of a blocked TSO queue, and
35 * wakes up the entire queue.
36 * Called from STG : yes
37 * Locks assumed : none
40 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
42 void awakenBlockedQueue(StgBlockingQueueElement *q, StgClosure *node);
44 void awakenBlockedQueue (Capability *cap, StgTSO *tso);
49 * Causes an OS thread to wake up and run the scheduler, if necessary.
55 * Put the specified thread on the run queue of the given Capability.
56 * Called from STG : yes
57 * Locks assumed : we own the Capability.
59 StgTSO * unblockOne (Capability *cap, StgTSO *tso);
61 /* raiseExceptionHelper */
62 StgWord raiseExceptionHelper (StgRegTable *reg, StgTSO *tso, StgClosure *exception);
64 /* findRetryFrameHelper */
65 StgWord findRetryFrameHelper (StgTSO *tso);
69 * Entry point for a new worker task.
70 * Called from STG : NO
71 * Locks assumed : none
73 void workerStart(Task *task);
76 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
77 void unlink_from_bq(StgTSO* tso, StgClosure* node);
78 void initThread(StgTSO *tso, nat stack_size, StgInt pri);
80 nat run_queue_len(void);
81 void awaken_blocked_queue(StgBlockingQueueElement *q, StgClosure *node);
82 void initThread(StgTSO *tso, nat stack_size);
84 char *info_type(StgClosure *closure); // dummy
85 char *info_type_by_ip(StgInfoTable *ip); // dummy
86 void awaken_blocked_queue(StgTSO *q);
87 void initThread(StgTSO *tso, nat stack_size);
90 /* Context switch flag.
91 * Locks required : none (conflicts are harmless)
93 extern int RTS_VAR(context_switch);
95 /* The state of the scheduler. This is used to control the sequence
96 * of events during shutdown, and when the runtime is interrupted
99 #define SCHED_RUNNING 0 /* running as normal */
100 #define SCHED_INTERRUPTING 1 /* ^C detected, before threads are deleted */
101 #define SCHED_SHUTTING_DOWN 2 /* final shutdown */
103 extern rtsBool RTS_VAR(sched_state);
106 * flag that tracks whether we have done any execution in this time slice.
108 #define ACTIVITY_YES 0 /* there has been activity in the current slice */
109 #define ACTIVITY_MAYBE_NO 1 /* no activity in the current slice */
110 #define ACTIVITY_INACTIVE 2 /* a complete slice has passed with no activity */
111 #define ACTIVITY_DONE_GC 3 /* like 2, but we've done a GC too */
113 /* Recent activity flag.
114 * Locks required : Transition from MAYBE_NO to INACTIVE
115 * happens in the timer signal, so it is atomic. Trnasition from
116 * INACTIVE to DONE_GC happens under sched_mutex. No lock required
117 * to set it to ACTIVITY_YES.
119 extern nat recent_activity;
122 * Locks required : sched_mutex
124 * In GranSim we have one run/blocked_queue per PE.
127 // run_queue_hds defined in GranSim.h
129 extern StgTSO *RTS_VAR(blackhole_queue);
130 #if !defined(THREADED_RTS)
131 extern StgTSO *RTS_VAR(blocked_queue_hd), *RTS_VAR(blocked_queue_tl);
132 extern StgTSO *RTS_VAR(sleeping_queue);
136 /* Set to rtsTrue if there are threads on the blackhole_queue, and
137 * it is possible that one or more of them may be available to run.
138 * This flag is set to rtsFalse after we've checked the queue, and
139 * set to rtsTrue just before we run some Haskell code. It is used
140 * to decide whether we should yield the Capability or not.
141 * Locks required : none (see scheduleCheckBlackHoles()).
143 extern rtsBool blackholes_need_checking;
145 #if defined(THREADED_RTS)
146 extern Mutex RTS_VAR(sched_mutex);
149 SchedulerStatus rts_mainLazyIO(HaskellObj p, /*out*/HaskellObj *ret);
151 /* Called by shutdown_handler(). */
152 void interruptStgRts (void);
154 nat run_queue_len (void);
156 void resurrectThreads (StgTSO *);
158 void printAllThreads(void);
163 void print_bq (StgClosure *node);
166 void print_bqe (StgBlockingQueueElement *bqe);
169 /* -----------------------------------------------------------------------------
170 * Some convenient macros/inline functions...
175 /* END_TSO_QUEUE and friends now defined in includes/StgMiscClosures.h */
177 /* Add a thread to the end of the run queue.
178 * NOTE: tso->link should be END_TSO_QUEUE before calling this macro.
179 * ASSUMES: cap->running_task is the current task.
182 appendToRunQueue (Capability *cap, StgTSO *tso)
184 ASSERT(tso->_link == END_TSO_QUEUE);
185 if (cap->run_queue_hd == END_TSO_QUEUE) {
186 cap->run_queue_hd = tso;
188 setTSOLink(cap, cap->run_queue_tl, tso);
190 cap->run_queue_tl = tso;
193 /* Push a thread on the beginning of the run queue. Used for
194 * newly awakened threads, so they get run as soon as possible.
195 * ASSUMES: cap->running_task is the current task.
198 pushOnRunQueue (Capability *cap, StgTSO *tso)
200 setTSOLink(cap, tso, cap->run_queue_hd);
201 cap->run_queue_hd = tso;
202 if (cap->run_queue_tl == END_TSO_QUEUE) {
203 cap->run_queue_tl = tso;
207 /* Pop the first thread off the runnable queue.
209 INLINE_HEADER StgTSO *
210 popRunQueue (Capability *cap)
212 StgTSO *t = cap->run_queue_hd;
213 ASSERT(t != END_TSO_QUEUE);
214 cap->run_queue_hd = t->_link;
215 t->_link = END_TSO_QUEUE; // no write barrier req'd
216 if (cap->run_queue_hd == END_TSO_QUEUE) {
217 cap->run_queue_tl = END_TSO_QUEUE;
222 /* Add a thread to the end of the blocked queue.
224 #if !defined(THREADED_RTS)
226 appendToBlockedQueue(StgTSO *tso)
228 ASSERT(tso->_link == END_TSO_QUEUE);
229 if (blocked_queue_hd == END_TSO_QUEUE) {
230 blocked_queue_hd = tso;
232 setTSOLink(&MainCapability, blocked_queue_tl, tso);
234 blocked_queue_tl = tso;
238 #if defined(THREADED_RTS)
240 appendToWakeupQueue (Capability *cap, StgTSO *tso)
242 ASSERT(tso->_link == END_TSO_QUEUE);
243 if (cap->wakeup_queue_hd == END_TSO_QUEUE) {
244 cap->wakeup_queue_hd = tso;
246 setTSOLink(cap, cap->wakeup_queue_tl, tso);
248 cap->wakeup_queue_tl = tso;
252 /* Check whether various thread queues are empty
254 INLINE_HEADER rtsBool
255 emptyQueue (StgTSO *q)
257 return (q == END_TSO_QUEUE);
260 INLINE_HEADER rtsBool
261 emptyRunQueue(Capability *cap)
263 return emptyQueue(cap->run_queue_hd);
266 #if defined(THREADED_RTS)
267 INLINE_HEADER rtsBool
268 emptyWakeupQueue(Capability *cap)
270 return emptyQueue(cap->wakeup_queue_hd);
274 #if !defined(THREADED_RTS)
275 #define EMPTY_BLOCKED_QUEUE() (emptyQueue(blocked_queue_hd))
276 #define EMPTY_SLEEPING_QUEUE() (emptyQueue(sleeping_queue))
279 INLINE_HEADER rtsBool
280 emptyThreadQueues(Capability *cap)
282 return emptyRunQueue(cap)
283 #if !defined(THREADED_RTS)
284 && EMPTY_BLOCKED_QUEUE() && EMPTY_SLEEPING_QUEUE()
289 #endif /* !IN_STG_CODE */
291 #endif /* SCHEDULE_H */