Added system thread manager class.

src/isolate.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 113 matching lines @@
 #endif
   thread_id_ = ThreadId::Current();
 }
 
 
 v8::TryCatch* ThreadLocalTop::TryCatchHandler() {
   return TRY_CATCH_FROM_ADDRESS(try_catch_handler_address());
 }
 
 
+int SystemThreadManager::NumberOfParallelSystemThreads(
+    ParallelSystemComponent type) {
+  int number_of_cores = OS::NumberOfCores();
+  if (type == PARALLEL_SWEEPING) {
+    return number_of_cores;
+  } else if (type == CONCURRENT_SWEEPING) {
+    return number_of_cores - 1;
+  } else if (type == PARALLEL_MARKING) {
+    return number_of_cores;

[Michael Starzinger, 2013/02/27 12:13:09]

Let's cap the number of threads to a certain maximum (I would propose 4 for
now), because I don't want V8 to spin up 32 threads on high-end machines.

[Hannes Payer (out of office), 2013/02/27 12:43:29]

Done.

+  }
+  return 1;
+}
+
+
 // Create a dummy thread that will wait forever on a semaphore. The only
 // purpose for this thread is to have some stack area to save essential data
 // into for use by a stacks only core dump (aka minidump).
 class PreallocatedMemoryThread: public Thread {
  public:
   char* data() {
     if (data_ready_semaphore_ != NULL) {
       // Initial access is guarded until the data has been published.
       data_ready_semaphore_->Wait();
       delete data_ready_semaphore_;
@@ skipping 1602 matching lines @@
 
 void Isolate::GlobalTearDown() {
   delete thread_data_table_;
 }
 
 
 void Isolate::Deinit() {
   if (state_ == INITIALIZED) {
     TRACE_ISOLATE(deinit);
 
-    if (FLAG_concurrent_sweeping || FLAG_parallel_sweeping) {
+    if (FLAG_sweeper_threads > 0) {
       for (int i = 0; i < FLAG_sweeper_threads; i++) {
         sweeper_thread_[i]->Stop();
         delete sweeper_thread_[i];
       }
       delete[] sweeper_thread_;
     }
 
-    if (FLAG_parallel_marking) {
+    if (FLAG_marking_threads > 0) {
       for (int i = 0; i < FLAG_marking_threads; i++) {
         marking_thread_[i]->Stop();
         delete marking_thread_[i];
       }
       delete[] marking_thread_;
     }
 
     if (FLAG_parallel_recompilation) optimizing_compiler_thread_.Stop();
 
     if (FLAG_hydrogen_stats) HStatistics::Instance()->Print();
@@ skipping 357 matching lines @@
 
   if (!Serializer::enabled()) {
     // Ensure that the stub failure trampoline has been generated.
     HandleScope scope(this);
     CodeStub::GenerateFPStubs();
     StubFailureTrampolineStub::GenerateAheadOfTime();
   }
 
   if (FLAG_parallel_recompilation) optimizing_compiler_thread_.Start();
 
-  if (FLAG_parallel_marking) {
-    if (FLAG_marking_threads < 1) {
-      FLAG_marking_threads = 1;
-    }
+  if (FLAG_parallel_marking && FLAG_marking_threads == 0) {
+    FLAG_marking_threads = SystemThreadManager::
+        NumberOfParallelSystemThreads(
+            SystemThreadManager::PARALLEL_MARKING);
+  }
+  if (FLAG_marking_threads > 0) {
     marking_thread_ = new MarkingThread*[FLAG_marking_threads];
     for (int i = 0; i < FLAG_marking_threads; i++) {
       marking_thread_[i] = new MarkingThread(this);
       marking_thread_[i]->Start();
     }
   }
 
-  if (FLAG_parallel_sweeping || FLAG_concurrent_sweeping) {
-    if (FLAG_sweeper_threads < 1) {
-      FLAG_sweeper_threads = 1;
+  if (FLAG_sweeper_threads == 0) {
+    if (FLAG_concurrent_sweeping) {
+      FLAG_sweeper_threads = SystemThreadManager::
+          NumberOfParallelSystemThreads(
+              SystemThreadManager::CONCURRENT_SWEEPING);
+    } else if (FLAG_parallel_sweeping) {
+      FLAG_sweeper_threads = SystemThreadManager::
+          NumberOfParallelSystemThreads(
+              SystemThreadManager::PARALLEL_SWEEPING);
     }
+  }
+  if (FLAG_sweeper_threads > 0) {
     sweeper_thread_ = new SweeperThread*[FLAG_sweeper_threads];
     for (int i = 0; i < FLAG_sweeper_threads; i++) {
       sweeper_thread_[i] = new SweeperThread(this);
       sweeper_thread_[i]->Start();
     }
   }
   return true;
 }
 
 
@@ skipping 114 matching lines @@
 
 #ifdef DEBUG
 #define ISOLATE_FIELD_OFFSET(type, name, ignored)                       \
 const intptr_t Isolate::name##_debug_offset_ = OFFSET_OF(Isolate, name##_);
 ISOLATE_INIT_LIST(ISOLATE_FIELD_OFFSET)
 ISOLATE_INIT_ARRAY_LIST(ISOLATE_FIELD_OFFSET)
 #undef ISOLATE_FIELD_OFFSET
 #endif
 
 } }  // namespace v8::internal