static void mark_root (void *user, StgClosure **root);
static void zero_static_object_list (StgClosure* first_static);
static nat initialise_N (rtsBool force_major_gc);
-static void alloc_gc_threads (void);
static void init_collected_gen (nat g, nat threads);
static void init_uncollected_gen (nat g, nat threads);
static void init_gc_thread (gc_thread *t);
static void scavenge_until_all_done (void);
static nat inc_running (void);
static nat dec_running (void);
-static void wakeup_gc_threads (nat n_threads);
-static void shutdown_gc_threads (nat n_threads);
+static void wakeup_gc_threads (nat n_threads, nat me);
+static void shutdown_gc_threads (nat n_threads, nat me);
+static void continue_gc_threads (nat n_threads, nat me);
#if 0 && defined(DEBUG)
static void gcCAFs (void);
-------------------------------------------------------------------------- */
void
-GarbageCollect ( rtsBool force_major_gc )
+GarbageCollect (rtsBool force_major_gc,
+ nat gc_type USED_IF_THREADS,
+ Capability *cap USED_IF_THREADS)
{
bdescr *bd;
step *stp;
*/
n = initialise_N(force_major_gc);
- /* Allocate + initialise the gc_thread structures.
- */
- alloc_gc_threads();
-
/* Start threads, so they can be spinning up while we finish initialisation.
*/
start_gc_threads();
+#if defined(THREADED_RTS)
/* How many threads will be participating in this GC?
- * We don't try to parallelise minor GC, or mark/compact/sweep GC.
+ * We don't try to parallelise minor GCs (unless the user asks for
+ * it with +RTS -gn0), or mark/compact/sweep GC.
*/
-#if defined(THREADED_RTS)
- if (n < (4*1024*1024 / BLOCK_SIZE) || oldest_gen->steps[0].mark) {
- n_gc_threads = 1;
+ if (gc_type == PENDING_GC_PAR) {
+ n_gc_threads = RtsFlags.ParFlags.nNodes;
} else {
- n_gc_threads = RtsFlags.ParFlags.gcThreads;
+ n_gc_threads = 1;
}
#else
n_gc_threads = 1;
#endif
+
trace(TRACE_gc|DEBUG_gc, "GC (gen %d): %d KB to collect, %ld MB in use, using %d thread(s)",
N, n * (BLOCK_SIZE / 1024), mblocks_allocated, n_gc_threads);
}
// this is the main thread
+#ifdef THREADED_RTS
+ if (n_gc_threads == 1) {
+ gct = gc_threads[0];
+ } else {
+ gct = gc_threads[cap->no];
+ }
+#else
gct = gc_threads[0];
+#endif
/* -----------------------------------------------------------------------
* follow all the roots that we know about:
// NB. do this after the mutable lists have been saved above, otherwise
// the other GC threads will be writing into the old mutable lists.
inc_running();
- wakeup_gc_threads(n_gc_threads);
+ wakeup_gc_threads(n_gc_threads, gct->thread_index);
for (g = RtsFlags.GcFlags.generations-1; g > N; g--) {
scavenge_mutable_list(&generations[g]);
break;
}
- shutdown_gc_threads(n_gc_threads);
+ shutdown_gc_threads(n_gc_threads, gct->thread_index);
// Update pointers from the Task list
update_task_list();
slop = calcLiveBlocks() * BLOCK_SIZE_W - live;
stat_endGC(allocated, live, copied, N, max_copied, avg_copied, slop);
+ // Guess which generation we'll collect *next* time
+ initialise_N(force_major_gc);
+
#if defined(RTS_USER_SIGNALS)
if (RtsFlags.MiscFlags.install_signal_handlers) {
// unblock signals again
}
#endif
+ continue_gc_threads(n_gc_threads, gct->thread_index);
+
RELEASE_SM_LOCK;
gct = saved_gct;
Initialise the gc_thread structures.
-------------------------------------------------------------------------- */
+#define GC_THREAD_INACTIVE 0
+#define GC_THREAD_STANDING_BY 1
+#define GC_THREAD_RUNNING 2
+#define GC_THREAD_WAITING_TO_CONTINUE 3
+
static gc_thread *
alloc_gc_thread (int n)
{
#ifdef THREADED_RTS
t->id = 0;
- initCondition(&t->wake_cond);
- initMutex(&t->wake_mutex);
- t->wakeup = rtsTrue; // starts true, so we can wait for the
+ initSpinLock(&t->gc_spin);
+ initSpinLock(&t->mut_spin);
+ ACQUIRE_SPIN_LOCK(&t->gc_spin);
+ t->wakeup = GC_THREAD_INACTIVE; // starts true, so we can wait for the
// thread to start up, see wakeup_gc_threads
- t->exit = rtsFalse;
#endif
t->thread_index = n;
}
-static void
-alloc_gc_threads (void)
+void
+initGcThreads (void)
{
if (gc_threads == NULL) {
#if defined(THREADED_RTS)
nat i;
- gc_threads = stgMallocBytes (RtsFlags.ParFlags.gcThreads *
+ gc_threads = stgMallocBytes (RtsFlags.ParFlags.nNodes *
sizeof(gc_thread*),
"alloc_gc_threads");
- for (i = 0; i < RtsFlags.ParFlags.gcThreads; i++) {
+ for (i = 0; i < RtsFlags.ParFlags.nNodes; i++) {
gc_threads[i] = alloc_gc_thread(i);
}
#else
}
#if defined(THREADED_RTS)
-//
-// gc_thread_work(): Scavenge until there's no work left to do and all
-// the running threads are idle.
-//
-static void
-gc_thread_work (void)
+
+void
+gcWorkerThread (Capability *cap)
{
- // gc_running_threads has already been incremented for us; this is
- // a worker thread and the main thread bumped gc_running_threads
- // before waking us up.
+ cap->in_gc = rtsTrue;
+
+ gct = gc_threads[cap->no];
+ gct->id = osThreadId();
+ // Wait until we're told to wake up
+ RELEASE_SPIN_LOCK(&gct->mut_spin);
+ gct->wakeup = GC_THREAD_STANDING_BY;
+ debugTrace(DEBUG_gc, "GC thread %d standing by...", gct->thread_index);
+ ACQUIRE_SPIN_LOCK(&gct->gc_spin);
+
+#ifdef USE_PAPI
+ // start performance counters in this thread...
+ if (gct->papi_events == -1) {
+ papi_init_eventset(&gct->papi_events);
+ }
+ papi_thread_start_gc1_count(gct->papi_events);
+#endif
+
// Every thread evacuates some roots.
gct->evac_step = 0;
markSomeCapabilities(mark_root, gct, gct->thread_index, n_gc_threads,
rtsTrue/*prune sparks*/);
scavenge_until_all_done();
-}
-
-
-static void
-gc_thread_mainloop (void)
-{
- while (!gct->exit) {
-
- // Wait until we're told to wake up
- ACQUIRE_LOCK(&gct->wake_mutex);
- gct->wakeup = rtsFalse;
- while (!gct->wakeup) {
- debugTrace(DEBUG_gc, "GC thread %d standing by...",
- gct->thread_index);
- waitCondition(&gct->wake_cond, &gct->wake_mutex);
- }
- RELEASE_LOCK(&gct->wake_mutex);
- if (gct->exit) break;
-
+
#ifdef USE_PAPI
- // start performance counters in this thread...
- if (gct->papi_events == -1) {
- papi_init_eventset(&gct->papi_events);
- }
- papi_thread_start_gc1_count(gct->papi_events);
+ // count events in this thread towards the GC totals
+ papi_thread_stop_gc1_count(gct->papi_events);
#endif
- gc_thread_work();
+ // Wait until we're told to continue
+ RELEASE_SPIN_LOCK(&gct->gc_spin);
+ gct->wakeup = GC_THREAD_WAITING_TO_CONTINUE;
+ debugTrace(DEBUG_gc, "GC thread %d waiting to continue...",
+ gct->thread_index);
+ ACQUIRE_SPIN_LOCK(&gct->mut_spin);
+ debugTrace(DEBUG_gc, "GC thread %d on my way...", gct->thread_index);
+}
-#ifdef USE_PAPI
- // count events in this thread towards the GC totals
- papi_thread_stop_gc1_count(gct->papi_events);
-#endif
- }
-}
#endif
-#if defined(THREADED_RTS)
-static void
-gc_thread_entry (gc_thread *my_gct)
+void
+waitForGcThreads (Capability *cap USED_IF_THREADS)
{
- gct = my_gct;
- debugTrace(DEBUG_gc, "GC thread %d starting...", gct->thread_index);
- gct->id = osThreadId();
- gc_thread_mainloop();
-}
+#if defined(THREADED_RTS)
+ nat n_threads = RtsFlags.ParFlags.nNodes;
+ nat me = cap->no;
+ nat i, j;
+ rtsBool retry = rtsTrue;
+
+ while(retry) {
+ for (i=0; i < n_threads; i++) {
+ if (i == me) continue;
+ if (gc_threads[i]->wakeup != GC_THREAD_STANDING_BY) {
+ prodCapability(&capabilities[i], cap->running_task);
+ }
+ }
+ for (j=0; j < 10000000; j++) {
+ retry = rtsFalse;
+ for (i=0; i < n_threads; i++) {
+ if (i == me) continue;
+ write_barrier();
+ setContextSwitches();
+ if (gc_threads[i]->wakeup != GC_THREAD_STANDING_BY) {
+ retry = rtsTrue;
+ }
+ }
+ if (!retry) break;
+ }
+ }
#endif
+}
static void
start_gc_threads (void)
{
#if defined(THREADED_RTS)
- nat i;
- OSThreadId id;
- static rtsBool done = rtsFalse;
-
gc_running_threads = 0;
initMutex(&gc_running_mutex);
-
- if (!done) {
- // Start from 1: the main thread is 0
- for (i = 1; i < RtsFlags.ParFlags.gcThreads; i++) {
- createOSThread(&id, (OSThreadProc*)&gc_thread_entry,
- gc_threads[i]);
- }
- done = rtsTrue;
- }
#endif
}
static void
-wakeup_gc_threads (nat n_threads USED_IF_THREADS)
+wakeup_gc_threads (nat n_threads USED_IF_THREADS, nat me USED_IF_THREADS)
{
#if defined(THREADED_RTS)
nat i;
- for (i=1; i < n_threads; i++) {
+ for (i=0; i < n_threads; i++) {
+ if (i == me) continue;
inc_running();
debugTrace(DEBUG_gc, "waking up gc thread %d", i);
- do {
- ACQUIRE_LOCK(&gc_threads[i]->wake_mutex);
- if (gc_threads[i]->wakeup) {
- RELEASE_LOCK(&gc_threads[i]->wake_mutex);
- continue;
- } else {
- break;
- }
- } while (1);
- gc_threads[i]->wakeup = rtsTrue;
- signalCondition(&gc_threads[i]->wake_cond);
- RELEASE_LOCK(&gc_threads[i]->wake_mutex);
+ if (gc_threads[i]->wakeup != GC_THREAD_STANDING_BY) barf("wakeup_gc_threads");
+
+ gc_threads[i]->wakeup = GC_THREAD_RUNNING;
+ ACQUIRE_SPIN_LOCK(&gc_threads[i]->mut_spin);
+ RELEASE_SPIN_LOCK(&gc_threads[i]->gc_spin);
}
#endif
}
// standby state, otherwise they may still be executing inside
// any_work(), and may even remain awake until the next GC starts.
static void
-shutdown_gc_threads (nat n_threads USED_IF_THREADS)
+shutdown_gc_threads (nat n_threads USED_IF_THREADS, nat me USED_IF_THREADS)
{
#if defined(THREADED_RTS)
nat i;
- rtsBool wakeup;
- for (i=1; i < n_threads; i++) {
- do {
- ACQUIRE_LOCK(&gc_threads[i]->wake_mutex);
- wakeup = gc_threads[i]->wakeup;
- // wakeup is false while the thread is waiting
- RELEASE_LOCK(&gc_threads[i]->wake_mutex);
- } while (wakeup);
+ for (i=0; i < n_threads; i++) {
+ if (i == me) continue;
+ while (gc_threads[i]->wakeup != GC_THREAD_WAITING_TO_CONTINUE) { write_barrier(); }
+ }
+#endif
+}
+
+static void
+continue_gc_threads (nat n_threads USED_IF_THREADS, nat me USED_IF_THREADS)
+{
+#if defined(THREADED_RTS)
+ nat i;
+ for (i=0; i < n_threads; i++) {
+ if (i == me) continue;
+ if (gc_threads[i]->wakeup != GC_THREAD_WAITING_TO_CONTINUE) barf("continue_gc_threads");
+
+ gc_threads[i]->wakeup = GC_THREAD_INACTIVE;
+ ACQUIRE_SPIN_LOCK(&gc_threads[i]->gc_spin);
+ RELEASE_SPIN_LOCK(&gc_threads[i]->mut_spin);
}
#endif
}
projects / ghc-hetmet.git / blobdiff