Switch gc_intrays_clearing to use condvar.

MoarVM · Jul 25, 2017 · 54fb63c · 54fb63c
1 parent 4d0a9d1
commit 54fb63c
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Showing 3 changed files with 12 additions and 8 deletions.
diff --git a/src/core/instance.h b/src/core/instance.h
@@ -162,13 +162,13 @@ struct MVMInstance {
     AO_t gc_finish;
     uv_cond_t cond_gc_finish;
 
-    /* Whether the coordinator considers all in-trays clear. */
+    /* Whether the coordinator considers all in-trays clear, and condition
+     * variable for when it changes. */
     AO_t gc_intrays_clearing;
+    uv_cond_t cond_gc_intrays_clearing;
 
-    /* The number of threads that have yet to acknowledge the finish, and
-     * condition variable for when it changes. */
+    /* The number of threads that have yet to acknowledge the finish. */
     AO_t gc_ack;
-    uv_cond_t cond_gc_ack;
 
     /* Linked list (via forwarder) of STables to free. */
     MVMSTable *stables_to_free;

diff --git a/src/gc/orchestrate.c b/src/gc/orchestrate.c
@@ -180,14 +180,18 @@ static void finish_gc(MVMThreadContext *tc, MVMuint8 gen, MVMuint8 is_coordinato
 
         GCDEBUG_LOG(tc, MVM_GC_DEBUG_ORCHESTRATE,
             "Thread %d run %d : Co-ordinator signalling in-trays clear\n");
+        uv_mutex_lock(&tc->instance->mutex_gc_orchestrate);
         MVM_store(&tc->instance->gc_intrays_clearing, 0);
+        uv_cond_broadcast(&tc->instance->cond_gc_intrays_clearing);
+        uv_mutex_unlock(&tc->instance->mutex_gc_orchestrate);
     }
     else {
         GCDEBUG_LOG(tc, MVM_GC_DEBUG_ORCHESTRATE,
             "Thread %d run %d : Waiting for in-tray clearing completion\n");
+        uv_mutex_lock(&tc->instance->mutex_gc_orchestrate);
         while (MVM_load(&tc->instance->gc_intrays_clearing))
-            for (i = 0; i < 1000; i++)
-                ; /* XXX Something HT-efficienter. */
+            uv_cond_wait(&tc->instance->cond_gc_intrays_clearing, &tc->instance->mutex_gc_orchestrate);
+        uv_mutex_unlock(&tc->instance->mutex_gc_orchestrate);
         GCDEBUG_LOG(tc, MVM_GC_DEBUG_ORCHESTRATE,
             "Thread %d run %d : Got in-tray clearing complete notice\n");
     }

diff --git a/src/moar.c b/src/moar.c
@@ -100,7 +100,7 @@ MVMInstance * MVM_vm_create_instance(void) {
     init_mutex(instance->mutex_gc_orchestrate, "GC orchestration");
     init_cond(instance->cond_gc_start, "GC start");
     init_cond(instance->cond_gc_finish, "GC finish");
-    init_cond(instance->cond_gc_ack, "GC ack");
+    init_cond(instance->cond_gc_intrays_clearing, "GC intrays clearing");
 
     /* Create fixed size allocator. */
     instance->fsa = MVM_fixed_size_create(instance->main_thread);
@@ -442,7 +442,7 @@ void MVM_vm_destroy_instance(MVMInstance *instance) {
     MVM_free(instance->permroot_descriptions);
     uv_cond_destroy(&instance->cond_gc_start);
     uv_cond_destroy(&instance->cond_gc_finish);
-    uv_cond_destroy(&instance->cond_gc_ack);
+    uv_cond_destroy(&instance->cond_gc_intrays_clearing);
     uv_mutex_destroy(&instance->mutex_gc_orchestrate);
 
     /* Clean up Hash of HLLConfig. */