* - Hp += n ==> Hp_adj(n)
* - R1.i ==> R1 (similarly for R1.w, R1.cl etc.)
* - You need to explicitly dereference variables; eg.
- * context_switch ==> CInt[context_switch]
+ * alloc_blocks ==> CInt[alloc_blocks]
* - convert all word offsets into byte offsets:
* - e ==> WDS(e)
* - sizeofW(StgFoo) ==> SIZEOF_StgFoo
extern StgWord rts_breakpoint_io_action[];
// Schedule.c
-extern int RTS_VAR(context_switch);
extern StgWord RTS_VAR(blocked_queue_hd), RTS_VAR(blocked_queue_tl);
extern StgWord RTS_VAR(sleeping_queue);
extern StgWord RTS_VAR(blackhole_queue);
field_offset(Capability, r);
field_offset(Capability, lock);
struct_field(Capability, mut_lists);
+ struct_field(Capability, context_switch);
struct_field(bdescr, start);
struct_field(bdescr, free);
cap->free_trec_chunks = END_STM_CHUNK_LIST;
cap->free_trec_headers = NO_TREC;
cap->transaction_tokens = 0;
+ cap->context_switch = 0;
}
/* ---------------------------------------------------------------------------
}
/* ----------------------------------------------------------------------------
+ * setContextSwitches: cause all capabilities to context switch as
+ * soon as possible.
+ * ------------------------------------------------------------------------- */
+
+void setContextSwitches(void)
+{
+ nat i;
+ for (i=0; i < n_capabilities; i++) {
+ capabilities[i].context_switch = 1;
+ }
+}
+
+/* ----------------------------------------------------------------------------
* Give a Capability to a Task. The task must currently be sleeping
* on its condition variable.
*
releaseCapability_(other_cap);
} else {
appendToWakeupQueue(my_cap,other_cap,tso);
+ other_cap->context_switch = 1;
// someone is running on this Capability, so it cannot be
// freed without first checking the wakeup queue (see
// releaseCapability_).
// each GC.
bdescr **mut_lists;
+ // Context switch flag. We used to have one global flag, now one
+ // per capability. Locks required : none (conflicts are harmless)
+ int context_switch;
+
#if defined(THREADED_RTS)
// Worker Tasks waiting in the wings. Singly-linked.
Task *spare_workers;
#endif /* !THREADED_RTS */
+// cause all capabilities to context switch as soon as possible.
+void setContextSwitches(void);
+
// Free a capability on exit
void freeCapability (Capability *cap);
CLOSE_NURSERY(); \
CurrentNursery = bdescr_link(CurrentNursery); \
OPEN_NURSERY(); \
- if (CInt[context_switch] != 0 :: CInt) { \
+ if (Capability_context_switch(MyCapability()) != 0 :: CInt) { \
R1 = ThreadYielding; \
goto sched; \
} else { \
// context switching: sometimes the scheduler can invoke
// the interpreter with context_switch == 1, particularly
// if the -C0 flag has been given on the cmd line.
- if (context_switch) {
+ if (cap->context_switch) {
Sp--; Sp[0] = (W_)&stg_enter_info;
RETURN_TO_SCHEDULER(ThreadInterpret, ThreadYielding);
}
foreign "C" scheduleThread(MyCapability() "ptr", threadid "ptr") [];
// switch at the earliest opportunity
- CInt[context_switch] = 1 :: CInt;
+ Capability_context_switch(MyCapability()) = 1 :: CInt;
RET_P(threadid);
}
foreign "C" scheduleThreadOn(MyCapability() "ptr", cpu, threadid "ptr") [];
// switch at the earliest opportunity
- CInt[context_switch] = 1 :: CInt;
+ Capability_context_switch(MyCapability()) = 1 :: CInt;
RET_P(threadid);
}
*/
rtsBool blackholes_need_checking = rtsFalse;
-/* flag set by signal handler to precipitate a context switch
- * LOCK: none (just an advisory flag)
- */
-int context_switch = 0;
-
/* flag that tracks whether we have done any execution in this time slice.
* LOCK: currently none, perhaps we should lock (but needs to be
* updated in the fast path of the scheduler).
*/
if (RtsFlags.ConcFlags.ctxtSwitchTicks == 0
&& !emptyThreadQueues(cap)) {
- context_switch = 1;
+ cap->context_switch = 1;
}
run_thread:
"--<< thread %ld (%s) stopped: HeapOverflow",
(long)t->id, whatNext_strs[t->what_next]);
- if (context_switch) {
+ if (cap->context_switch) {
// Sometimes we miss a context switch, e.g. when calling
// primitives in a tight loop, MAYBE_GC() doesn't check the
// context switch flag, and we end up waiting for a GC.
// See #1984, and concurrent/should_run/1984
- context_switch = 0;
+ cap->context_switch = 0;
addToRunQueue(cap,t);
} else {
pushOnRunQueue(cap,t);
// the CPU because the tick always arrives during GC). This way
// penalises threads that do a lot of allocation, but that seems
// better than the alternative.
- context_switch = 0;
+ cap->context_switch = 0;
/* 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
return cap; // NOTE: task->cap might have changed here
}
+ setContextSwitches();
for (i=0; i < n_capabilities; i++) {
debugTrace(DEBUG_sched, "ready_to_gc, grabbing all the capabilies (%d/%d)", i, n_capabilities);
if (cap != &capabilities[i]) {
// all the Capabilities, but even so it's a slightly
// unsavoury invariant.
task->cap = pcap;
- context_switch = 1;
waitForReturnCapability(&pcap, task);
if (pcap != &capabilities[i]) {
barf("scheduleDoGC: got the wrong capability");
blackhole_queue = END_TSO_QUEUE;
- context_switch = 0;
sched_state = SCHED_RUNNING;
recent_activity = ACTIVITY_YES;
interruptStgRts(void)
{
sched_state = SCHED_INTERRUPTING;
- context_switch = 1;
+ setContextSwitches();
wakeUpRts();
}
void initThread(StgTSO *tso, nat stack_size);
#endif
-/* Context switch flag.
- * Locks required : none (conflicts are harmless)
- */
-extern int RTS_VAR(context_switch);
-
/* The state of the scheduler. This is used to control the sequence
* of events during shutdown, and when the runtime is interrupted
* using ^C.
appendToRunQueue(cap,tso);
// we're holding a newly woken thread, make sure we context switch
// quickly so we can migrate it if necessary.
- context_switch = 1;
+ cap->context_switch = 1;
} else {
// we'll try to wake it up on the Capability it was last on.
wakeupThreadOnCapability(cap, tso->cap, tso);
}
#else
appendToRunQueue(cap,tso);
- context_switch = 1;
+ cap->context_switch = 1;
#endif
debugTrace(DEBUG_sched,
ticks_to_ctxt_switch--;
if (ticks_to_ctxt_switch <= 0) {
ticks_to_ctxt_switch = RtsFlags.ConcFlags.ctxtSwitchTicks;
- context_switch = 1; /* schedule a context switch */
+ setContextSwitches(); /* schedule a context switch */
}
}
stg_exit(EXIT_FAILURE);
}
+ MainCapability.context_switch = 1;
+
#endif /* THREADED_RTS */
// re-establish the signal handler, and carry on
sigemptyset(&signals);
sigaddset(&signals, sig);
sigprocmask(SIG_UNBLOCK, &signals, NULL);
-
- context_switch = 1;
}
/* -----------------------------------------------------------------------------