Revision: 16430
Author: [email protected]
Date: Thu Aug 29 14:03:38 2013 UTC
Log: Do not start sampler thread when CpuProfiler is active
Now that CpuProfiler sends does sampling on the profile event processing
thread there is no need to launch sampler thread. The latter is used only
for --prof profiler.
BUG=v8:2814
[email protected], [email protected]
Review URL: https://codereview.chromium.org/23011029
http://code.google.com/p/v8/source/detail?r=16430
Modified:
/branches/bleeding_edge/src/cpu-profiler.cc
/branches/bleeding_edge/src/cpu-profiler.h
/branches/bleeding_edge/src/log.cc
/branches/bleeding_edge/src/sampler.cc
/branches/bleeding_edge/src/sampler.h
=======================================
--- /branches/bleeding_edge/src/cpu-profiler.cc Thu Aug 29 10:42:55 2013 UTC
+++ /branches/bleeding_edge/src/cpu-profiler.cc Thu Aug 29 14:03:38 2013 UTC
@@ -137,26 +137,11 @@
// Schedule next sample. sampler_ is NULL in tests.
if (sampler_) sampler_->DoSample();
}
-
-
-void ProfilerEventsProcessor::ProcessEventsAndYield() {
- // Process ticks until we have any.
- if (ProcessTicks()) {
- // All ticks of the current dequeue_order are processed,
- // proceed to the next code event.
- ProcessCodeEvent();
- }
- YieldCPU();
-}
void ProfilerEventsProcessor::Run() {
while (running_) {
- if (Sampler::CanSampleOnProfilerEventsProcessorThread()) {
- ProcessEventsAndDoSample();
- } else {
- ProcessEventsAndYield();
- }
+ ProcessEventsAndDoSample();
}
// Process remaining tick events.
@@ -382,7 +367,6 @@
next_profile_uid_(1),
generator_(NULL),
processor_(NULL),
- need_to_stop_sampler_(false),
is_profiling_(false) {
}
@@ -396,7 +380,6 @@
next_profile_uid_(1),
generator_(test_generator),
processor_(test_processor),
- need_to_stop_sampler_(false),
is_profiling_(false) {
}
@@ -447,14 +430,8 @@
logger->LogAccessorCallbacks();
LogBuiltins();
// Enable stack sampling.
- if (Sampler::CanSampleOnProfilerEventsProcessorThread()) {
- sampler->SetHasProcessingThread(true);
- }
+ sampler->SetHasProcessingThread(true);
sampler->IncreaseProfilingDepth();
- if (!sampler->IsActive()) {
- sampler->Start();
- need_to_stop_sampler_ = true;
- }
processor_->StartSynchronously();
}
}
@@ -487,20 +464,14 @@
void CpuProfiler::StopProcessor() {
Logger* logger = isolate_->logger();
Sampler* sampler = reinterpret_cast<Sampler*>(logger->ticker_);
- sampler->DecreaseProfilingDepth();
is_profiling_ = false;
processor_->StopSynchronously();
delete processor_;
delete generator_;
processor_ = NULL;
generator_ = NULL;
- if (Sampler::CanSampleOnProfilerEventsProcessorThread()) {
- sampler->SetHasProcessingThread(false);
- }
- if (need_to_stop_sampler_) {
- sampler->Stop();
- need_to_stop_sampler_ = false;
- }
+ sampler->SetHasProcessingThread(false);
+ sampler->DecreaseProfilingDepth();
logger->is_logging_ = saved_is_logging_;
}
=======================================
--- /branches/bleeding_edge/src/cpu-profiler.h Thu Aug 29 10:42:55 2013 UTC
+++ /branches/bleeding_edge/src/cpu-profiler.h Thu Aug 29 14:03:38 2013 UTC
@@ -163,7 +163,6 @@
bool ProcessTicks();
void ProcessEventsAndDoSample();
- void ProcessEventsAndYield();
ProfileGenerator* generator_;
Sampler* sampler_;
@@ -266,7 +265,6 @@
ProfileGenerator* generator_;
ProfilerEventsProcessor* processor_;
bool saved_is_logging_;
- bool need_to_stop_sampler_;
bool is_profiling_;
DISALLOW_COPY_AND_ASSIGN(CpuProfiler);
=======================================
--- /branches/bleeding_edge/src/log.cc Thu Aug 29 10:42:55 2013 UTC
+++ /branches/bleeding_edge/src/log.cc Thu Aug 29 14:03:38 2013 UTC
@@ -626,9 +626,9 @@
}
void ClearProfiler() {
- DecreaseProfilingDepth();
profiler_ = NULL;
if (IsActive()) Stop();
+ DecreaseProfilingDepth();
}
private:
=======================================
--- /branches/bleeding_edge/src/sampler.cc Thu Aug 29 13:44:25 2013 UTC
+++ /branches/bleeding_edge/src/sampler.cc Thu Aug 29 14:03:38 2013 UTC
@@ -248,8 +248,25 @@
class SignalHandler : public AllStatic {
public:
- static inline void EnsureInstalled() {
- if (signal_handler_installed_) return;
+ static void SetUp() { if (!mutex_) mutex_ = new Mutex(); }
+ static void TearDown() { delete mutex_; }
+
+ static void IncreaseSamplerCount() {
+ LockGuard<Mutex> lock_guard(mutex_);
+ if (++client_count_ == 1) Install();
+ }
+
+ static void DecreaseSamplerCount() {
+ LockGuard<Mutex> lock_guard(mutex_);
+ if (--client_count_ == 0) Restore();
+ }
+
+ static bool Installed() {
+ return signal_handler_installed_;
+ }
+
+ private:
+ static void Install() {
struct sigaction sa;
sa.sa_sigaction = &HandleProfilerSignal;
sigemptyset(&sa.sa_mask);
@@ -258,23 +275,24 @@
(sigaction(SIGPROF, &sa, &old_signal_handler_) == 0);
}
- static inline void Restore() {
+ static void Restore() {
if (signal_handler_installed_) {
sigaction(SIGPROF, &old_signal_handler_, 0);
signal_handler_installed_ = false;
}
}
- static inline bool Installed() {
- return signal_handler_installed_;
- }
-
- private:
static void HandleProfilerSignal(int signal, siginfo_t* info, void*
context);
+ // Protects the process wide state below.
+ static Mutex* mutex_;
+ static int client_count_;
static bool signal_handler_installed_;
static struct sigaction old_signal_handler_;
};
+
+Mutex* SignalHandler::mutex_ = NULL;
+int SignalHandler::client_count_ = 0;
struct sigaction SignalHandler::old_signal_handler_;
bool SignalHandler::signal_handler_installed_ = false;
@@ -299,7 +317,7 @@
}
Sampler* sampler = isolate->logger()->sampler();
- if (sampler == NULL || !sampler->IsActive()) return;
+ if (sampler == NULL) return;
RegisterState state;
@@ -436,9 +454,6 @@
ASSERT(instance_->interval_ == sampler->interval());
instance_->active_samplers_.Add(sampler);
-#if defined(USE_SIGNALS)
- SignalHandler::EnsureInstalled();
-#endif
if (need_to_start) instance_->StartSynchronously();
}
@@ -457,9 +472,6 @@
if (instance_->active_samplers_.is_empty()) {
instance_to_remove = instance_;
instance_ = NULL;
-#if defined(USE_SIGNALS)
- SignalHandler::Restore();
-#endif
}
}
@@ -548,12 +560,18 @@
void Sampler::SetUp() {
+#if defined(USE_SIGNALS)
+ SignalHandler::SetUp();
+#endif
SamplerThread::SetUp();
}
void Sampler::TearDown() {
SamplerThread::TearDown();
+#if defined(USE_SIGNALS)
+ SignalHandler::TearDown();
+#endif
}
@@ -587,6 +605,22 @@
SamplerThread::RemoveActiveSampler(this);
SetActive(false);
}
+
+
+void Sampler::IncreaseProfilingDepth() {
+ NoBarrier_AtomicIncrement(&profiling_, 1);
+#if defined(USE_SIGNALS)
+ SignalHandler::IncreaseSamplerCount();
+#endif
+}
+
+
+void Sampler::DecreaseProfilingDepth() {
+#if defined(USE_SIGNALS)
+ SignalHandler::DecreaseSamplerCount();
+#endif
+ NoBarrier_AtomicIncrement(&profiling_, -1);
+}
void Sampler::SampleStack(const RegisterState& state) {
@@ -604,17 +638,6 @@
isolate_->cpu_profiler()->FinishTickSample();
}
}
-
-
-bool Sampler::CanSampleOnProfilerEventsProcessorThread() {
-#if defined(USE_SIGNALS)
- return true;
-#elif V8_OS_WIN || V8_OS_CYGWIN
- return true;
-#else
- return false;
-#endif
-}
#if defined(USE_SIGNALS)
=======================================
--- /branches/bleeding_edge/src/sampler.h Mon Aug 26 07:17:12 2013 UTC
+++ /branches/bleeding_edge/src/sampler.h Thu Aug 29 14:03:38 2013 UTC
@@ -99,16 +99,15 @@
return NoBarrier_Load(&profiling_) > 0 &&
!NoBarrier_Load(&has_processing_thread_);
}
- void IncreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_,
1); }
- void DecreaseProfilingDepth() { NoBarrier_AtomicIncrement(&profiling_,
-1); }
+ void IncreaseProfilingDepth();
+ void DecreaseProfilingDepth();
// Whether the sampler is running (that is, consumes resources).
bool IsActive() const { return NoBarrier_Load(&active_); }
+ void DoSample();
// If true next sample must be initiated on the profiler event processor
// thread right after latest sample is processed.
- static bool CanSampleOnProfilerEventsProcessorThread();
- void DoSample();
void SetHasProcessingThread(bool value) {
NoBarrier_Store(&has_processing_thread_, value);
}
--
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