[sgen] Always use one concurrent worker
[mono.git] / mono / sgen / sgen-workers.c
index f32d593186d9471b1f1e73f12f30a30df259c8e9..cc1930bcc2f443a65b4c536208051e89a119e94f 100644 (file)
@@ -20,6 +20,7 @@
 #include "mono/sgen/sgen-client.h"
 
 static int workers_num;
+static int active_workers_num;
 static volatile gboolean forced_stop;
 static WorkerData *workers_data;
 static SgenWorkerCallback worker_init_cb;
@@ -31,6 +32,8 @@ static SgenWorkerCallback worker_init_cb;
  * gracefully finished, so it can restart them.
  */
 static mono_mutex_t finished_lock;
+static volatile gboolean workers_finished;
+static int worker_awakenings;
 
 static SgenSectionGrayQueue workers_distribute_gray_queue;
 static gboolean workers_distribute_gray_queue_inited;
@@ -101,9 +104,10 @@ sgen_workers_ensure_awake (void)
         * or when the last worker is enqueuing preclean work. In both cases we can't
         * have a worker working using a nopar context, which means it is safe.
         */
-       idle_func_object_ops = (workers_num > 1) ? idle_func_object_ops_par : idle_func_object_ops_nopar;
+       idle_func_object_ops = (active_workers_num > 1) ? idle_func_object_ops_par : idle_func_object_ops_nopar;
+       workers_finished = FALSE;
 
-       for (i = 0; i < workers_num; i++) {
+       for (i = 0; i < active_workers_num; i++) {
                State old_state;
                gboolean did_set_state;
 
@@ -134,7 +138,7 @@ worker_try_finish (WorkerData *data)
 
        mono_os_mutex_lock (&finished_lock);
 
-       for (i = 0; i < workers_num; i++) {
+       for (i = 0; i < active_workers_num; i++) {
                if (state_is_working_or_enqueued (workers_data [i].state))
                        working++;
        }
@@ -147,6 +151,7 @@ worker_try_finish (WorkerData *data)
                if (callback) {
                        finish_callback = NULL;
                        callback ();
+                       worker_awakenings = 0;
                        /* Make sure each worker has a chance of seeing the enqueued jobs */
                        sgen_workers_ensure_awake ();
                        SGEN_ASSERT (0, data->state == STATE_WORK_ENQUEUED, "Why did we fail to set our own state to ENQUEUED");
@@ -171,6 +176,7 @@ worker_try_finish (WorkerData *data)
        if (working == 2)
                idle_func_object_ops = idle_func_object_ops_nopar;
 
+       workers_finished = TRUE;
        mono_os_mutex_unlock (&finished_lock);
 
        binary_protocol_worker_finish (sgen_timestamp (), forced_stop);
@@ -206,7 +212,7 @@ workers_get_work (WorkerData *data)
        if (major->is_concurrent) {
                GrayQueueSection *section = sgen_section_gray_queue_dequeue (&workers_distribute_gray_queue);
                if (section) {
-                       sgen_gray_object_enqueue_section (&data->private_gray_queue, section);
+                       sgen_gray_object_enqueue_section (&data->private_gray_queue, section, major->is_parallel);
                        return TRUE;
                }
        }
@@ -231,14 +237,14 @@ workers_steal_work (WorkerData *data)
 
        current_worker = (int) (data - workers_data);
 
-       for (i = 1; i < workers_num && !section; i++) {
-               int steal_worker = (current_worker + i) % workers_num;
+       for (i = 1; i < active_workers_num && !section; i++) {
+               int steal_worker = (current_worker + i) % active_workers_num;
                if (state_is_working_or_enqueued (workers_data [steal_worker].state))
                        section = sgen_gray_object_steal_section (&workers_data [steal_worker].private_gray_queue);
        }
 
        if (section) {
-               sgen_gray_object_enqueue_section (&data->private_gray_queue, section);
+               sgen_gray_object_enqueue_section (&data->private_gray_queue, section, TRUE);
                return TRUE;
        }
 
@@ -292,6 +298,15 @@ continue_idle_func (void *data_untyped)
        }
 }
 
+static gboolean
+should_work_func (void *data_untyped)
+{
+       WorkerData *data = (WorkerData*)data_untyped;
+       int current_worker = (int) (data - workers_data);
+
+       return current_worker < active_workers_num;
+}
+
 static void
 marker_idle_func (void *data_untyped)
 {
@@ -311,6 +326,12 @@ marker_idle_func (void *data_untyped)
                SGEN_ASSERT (0, !sgen_gray_object_queue_is_empty (&data->private_gray_queue), "How is our gray queue empty if we just got work?");
 
                sgen_drain_gray_stack (ctx);
+
+               if (data->private_gray_queue.num_sections > 16 && workers_finished && worker_awakenings < active_workers_num) {
+                       /* We bound the number of worker awakenings just to be sure */
+                       worker_awakenings++;
+                       sgen_workers_ensure_awake ();
+               }
        } else {
                worker_try_finish (data);
        }
@@ -345,7 +366,7 @@ sgen_workers_init (int num_workers, SgenWorkerCallback callback)
        void **workers_data_ptrs = (void **)alloca(num_workers * sizeof(void *));
 
        if (!sgen_get_major_collector ()->is_concurrent) {
-               sgen_thread_pool_init (num_workers, thread_pool_init_func, NULL, NULL, NULL);
+               sgen_thread_pool_init (num_workers, thread_pool_init_func, NULL, NULL, NULL, NULL);
                return;
        }
 
@@ -353,6 +374,7 @@ sgen_workers_init (int num_workers, SgenWorkerCallback callback)
        //g_print ("initing %d workers\n", num_workers);
 
        workers_num = num_workers;
+       active_workers_num = num_workers;
 
        workers_data = (WorkerData *)sgen_alloc_internal_dynamic (sizeof (WorkerData) * num_workers, INTERNAL_MEM_WORKER_DATA, TRUE);
        memset (workers_data, 0, sizeof (WorkerData) * num_workers);
@@ -364,7 +386,7 @@ sgen_workers_init (int num_workers, SgenWorkerCallback callback)
 
        worker_init_cb = callback;
 
-       sgen_thread_pool_init (num_workers, thread_pool_init_func, marker_idle_func, continue_idle_func, workers_data_ptrs);
+       sgen_thread_pool_init (num_workers, thread_pool_init_func, marker_idle_func, continue_idle_func, should_work_func, workers_data_ptrs);
 
        mono_counters_register ("# workers finished", MONO_COUNTER_GC | MONO_COUNTER_ULONG, &stat_workers_num_finished);
 }
@@ -381,6 +403,17 @@ sgen_workers_stop_all_workers (void)
        SGEN_ASSERT (0, sgen_workers_all_done (), "Can only signal enqueue work when in no work state");
 }
 
+void
+sgen_workers_set_num_active_workers (int num_workers)
+{
+       if (num_workers) {
+               SGEN_ASSERT (0, active_workers_num <= workers_num, "We can't start more workers than we initialized");
+               active_workers_num = num_workers;
+       } else {
+               active_workers_num = workers_num;
+       }
+}
+
 void
 sgen_workers_start_all_workers (SgenObjectOperations *object_ops_nopar, SgenObjectOperations *object_ops_par, SgenWorkersFinishCallback callback)
 {
@@ -388,6 +421,7 @@ sgen_workers_start_all_workers (SgenObjectOperations *object_ops_nopar, SgenObje
        idle_func_object_ops_nopar = object_ops_nopar;
        forced_stop = FALSE;
        finish_callback = callback;
+       worker_awakenings = 0;
        mono_memory_write_barrier ();
 
        sgen_workers_ensure_awake ();
@@ -405,7 +439,7 @@ sgen_workers_join (void)
        /* At this point all the workers have stopped. */
 
        SGEN_ASSERT (0, sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue), "Why is there still work left to do?");
-       for (i = 0; i < workers_num; ++i)
+       for (i = 0; i < active_workers_num; ++i)
                SGEN_ASSERT (0, sgen_gray_object_queue_is_empty (&workers_data [i].private_gray_queue), "Why is there still work left to do?");
 }
 
@@ -423,7 +457,7 @@ sgen_workers_have_idle_work (void)
        if (!sgen_section_gray_queue_is_empty (&workers_distribute_gray_queue))
                return TRUE;
 
-       for (i = 0; i < workers_num; ++i) {
+       for (i = 0; i < active_workers_num; ++i) {
                if (!sgen_gray_object_queue_is_empty (&workers_data [i].private_gray_queue))
                        return TRUE;
        }
@@ -436,7 +470,7 @@ sgen_workers_all_done (void)
 {
        int i;
 
-       for (i = 0; i < workers_num; i++) {
+       for (i = 0; i < active_workers_num; i++) {
                if (state_is_working_or_enqueued (workers_data [i].state))
                        return FALSE;
        }
@@ -459,6 +493,8 @@ sgen_workers_assert_gray_queue_is_empty (void)
 void
 sgen_workers_take_from_queue (SgenGrayQueue *queue)
 {
+       sgen_gray_object_spread (queue, sgen_workers_get_job_split_count ());
+
        for (;;) {
                GrayQueueSection *section = sgen_gray_object_dequeue_section (queue);
                if (!section)
@@ -484,7 +520,7 @@ sgen_workers_get_idle_func_object_ops (void)
 int
 sgen_workers_get_job_split_count (void)
 {
-       return (workers_num > 1) ? workers_num * 4 : 1;
+       return (active_workers_num > 1) ? active_workers_num * 4 : 1;
 }
 
 void