Reduce CPU usage when no isolates need to be profiled.

runtime/vm/dart_api_impl.cc

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "include/dart_api.h"
 #include "include/dart_mirrors_api.h"
 #include "include/dart_native_api.h"
 
 #include "platform/assert.h"
 #include "vm/bigint_operations.h"
 #include "vm/class_finalizer.h"
 #include "vm/compiler.h"
 #include "vm/dart.h"
 #include "vm/dart_api_impl.h"
 #include "vm/dart_api_message.h"
 #include "vm/dart_api_state.h"
 #include "vm/dart_entry.h"
 #include "vm/debuginfo.h"
 #include "vm/exceptions.h"
 #include "vm/flags.h"
 #include "vm/growable_array.h"
 #include "vm/message.h"
 #include "vm/message_handler.h"
 #include "vm/native_entry.h"
 #include "vm/object.h"
 #include "vm/object_store.h"
 #include "vm/port.h"
+#include "vm/profiler.h"
 #include "vm/resolver.h"
 #include "vm/reusable_handles.h"
 #include "vm/service.h"
 #include "vm/stack_frame.h"
 #include "vm/symbols.h"
 #include "vm/tags.h"
 #include "vm/timer.h"
 #include "vm/unicode.h"
 #include "vm/verifier.h"
 #include "vm/version.h"
@@ skipping 4983 matching lines @@
   }
   {
     NoGCScope no_gc;
     RawObject* raw_obj = obj.raw();
     isolate->heap()->SetPeer(raw_obj, peer);
   }
   return Api::Success();
 }
 
 
+// --- Profiler support ---
+
+DART_EXPORT void Dart_BlockProfiler() {
+  Isolate* isolate = Isolate::Current();
+  CHECK_ISOLATE(isolate);
+  IsolateProfilerData* profiler_data = isolate->profiler_data();
+  if (profiler_data == NULL) {
+    return;
+  }
+  profiler_data->Block();
+}
+
+
+DART_EXPORT void Dart_UnblockProfiler() {
+  Isolate* isolate = Isolate::Current();
+  CHECK_ISOLATE(isolate);
+  IsolateProfilerData* profiler_data = isolate->profiler_data();
+  if (profiler_data == NULL) {
+    return;
+  }
+  profiler_data->Unblock();
+}
+
+
 // --- Service support ---
 
 DART_EXPORT Dart_Isolate Dart_GetServiceIsolate(void* callback_data) {
   return Api::CastIsolate(Service::GetServiceIsolate(callback_data));
 }
 
 
 DART_EXPORT bool Dart_IsServiceRunning() {
   return Service::IsRunning();
 }
 
 
 DART_EXPORT void Dart_RegisterIsolateServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterIsolateEmbedderCallback(name, callback, user_data);
 }
 
 
 DART_EXPORT void Dart_RegisterRootServiceRequestCallback(
     const char* name,
     Dart_ServiceRequestCallback callback,
     void* user_data) {
   Service::RegisterRootEmbedderCallback(name, callback, user_data);
 }
 
 }  // namespace dart