Revision: 7140
Author: [email protected]
Date: Thu Mar 10 17:43:44 2011
Log: Update platform-solaris to support runtime profiling.
Landing patch by Ryan Dahl.
[email protected]
Original review: http://codereview.chromium.org/6674002/
Review URL: http://codereview.chromium.org/6667025
http://code.google.com/p/v8/source/detail?r=7140
Modified:
/branches/bleeding_edge/src/platform-solaris.cc
=======================================
--- /branches/bleeding_edge/src/platform-solaris.cc Mon Feb 21 09:17:26 2011
+++ /branches/bleeding_edge/src/platform-solaris.cc Thu Mar 10 17:43:44 2011
@@ -612,11 +612,16 @@
static pthread_t vm_tid_ = 0;
+static pthread_t GetThreadID() {
+ return pthread_self();
+}
+
+
static void ProfilerSignalHandler(int signal, siginfo_t* info, void*
context) {
USE(info);
if (signal != SIGPROF) return;
if (active_sampler_ == NULL || !active_sampler_->IsActive()) return;
- if (vm_tid_ != pthread_self()) return;
+ if (vm_tid_ != GetThreadID()) return;
TickSample sample_obj;
TickSample* sample = CpuProfiler::TickSampleEvent();
@@ -645,26 +650,90 @@
class Sampler::PlatformData : public Malloced {
public:
- PlatformData() {
- signal_handler_installed_ = false;
+ enum SleepInterval {
+ FULL_INTERVAL,
+ HALF_INTERVAL
+ };
+
+ explicit PlatformData(Sampler* sampler)
+ : sampler_(sampler),
+ signal_handler_installed_(false),
+ vm_tgid_(getpid()),
+ signal_sender_launched_(false) {
}
+ void SignalSender() {
+ while (sampler_->IsActive()) {
+ if (rate_limiter_.SuspendIfNecessary()) continue;
+ if (sampler_->IsProfiling() && RuntimeProfiler::IsEnabled()) {
+ SendProfilingSignal();
+ Sleep(HALF_INTERVAL);
+ RuntimeProfiler::NotifyTick();
+ Sleep(HALF_INTERVAL);
+ } else {
+ if (sampler_->IsProfiling()) SendProfilingSignal();
+ if (RuntimeProfiler::IsEnabled()) RuntimeProfiler::NotifyTick();
+ Sleep(FULL_INTERVAL);
+ }
+ }
+ }
+
+ void SendProfilingSignal() {
+ if (!signal_handler_installed_) return;
+ // There doesn't seem to be a robust way to deliver a signal to a
+ // particular thread that may have terminated already. We send the
+ // signal to the whole process hoping the right thread will get
+ // it.
+ kill(vm_tgid_, SIGPROF);
+ }
+
+ void Sleep(SleepInterval full_or_half) {
+ // Convert ms to us and subtract 100 us to compensate delays
+ // occuring during signal delivery.
+ useconds_t interval = sampler_->interval_ * 1000 - 100;
+ if (full_or_half == HALF_INTERVAL) interval /= 2;
+ int result = usleep(interval);
+#ifdef DEBUG
+ if (result != 0 && errno != EINTR) {
+ fprintf(stderr,
+ "SignalSender usleep error; interval = %u, errno = %d\n",
+ interval,
+ errno);
+ ASSERT(result == 0 || errno == EINTR);
+ }
+#endif
+ USE(result);
+ }
+
+ Sampler* sampler_;
bool signal_handler_installed_;
struct sigaction old_signal_handler_;
- struct itimerval old_timer_value_;
+ int vm_tgid_;
+ bool signal_sender_launched_;
+ pthread_t signal_sender_thread_;
+ RuntimeProfilerRateLimiter rate_limiter_;
};
+static void* SenderEntry(void* arg) {
+ Sampler::PlatformData* data =
+ reinterpret_cast<Sampler::PlatformData*>(arg);
+ data->SignalSender();
+ return 0;
+}
+
+
Sampler::Sampler(int interval)
: interval_(interval),
profiling_(false),
active_(false),
samples_taken_(0) {
- data_ = new PlatformData();
+ data_ = new PlatformData(this);
}
Sampler::~Sampler() {
+ ASSERT(!data_->signal_sender_launched_);
delete data_;
}
@@ -672,41 +741,50 @@
void Sampler::Start() {
// There can only be one active sampler at the time on POSIX
// platforms.
- if (active_sampler_ != NULL) return;
+ ASSERT(!IsActive());
+ vm_tid_ = GetThreadID();
// Request profiling signals.
struct sigaction sa;
sa.sa_sigaction = ProfilerSignalHandler;
sigemptyset(&sa.sa_mask);
- sa.sa_flags = SA_SIGINFO;
- if (sigaction(SIGPROF, &sa, &data_->old_signal_handler_) != 0) return;
- data_->signal_handler_installed_ = true;
-
- // Set the itimer to generate a tick for each interval.
- itimerval itimer;
- itimer.it_interval.tv_sec = interval_ / 1000;
- itimer.it_interval.tv_usec = (interval_ % 1000) * 1000;
- itimer.it_value.tv_sec = itimer.it_interval.tv_sec;
- itimer.it_value.tv_usec = itimer.it_interval.tv_usec;
- setitimer(ITIMER_PROF, &itimer, &data_->old_timer_value_);
+ sa.sa_flags = SA_RESTART | SA_SIGINFO;
+ data_->signal_handler_installed_ =
+ sigaction(SIGPROF, &sa, &data_->old_signal_handler_) == 0;
+
+ // Start a thread that sends SIGPROF signal to VM thread.
+ // Sending the signal ourselves instead of relying on itimer provides
+ // much better accuracy.
+ SetActive(true);
+ if (pthread_create(
+ &data_->signal_sender_thread_, NULL, SenderEntry, data_) == 0) {
+ data_->signal_sender_launched_ = true;
+ }
// Set this sampler as the active sampler.
active_sampler_ = this;
- active_ = true;
}
void Sampler::Stop() {
+ SetActive(false);
+
+ // Wait for signal sender termination (it will exit after setting
+ // active_ to false).
+ if (data_->signal_sender_launched_) {
+ Top::WakeUpRuntimeProfilerThreadBeforeShutdown();
+ pthread_join(data_->signal_sender_thread_, NULL);
+ data_->signal_sender_launched_ = false;
+ }
+
// Restore old signal handler
if (data_->signal_handler_installed_) {
- setitimer(ITIMER_PROF, &data_->old_timer_value_, NULL);
sigaction(SIGPROF, &data_->old_signal_handler_, 0);
data_->signal_handler_installed_ = false;
}
// This sampler is no longer the active sampler.
active_sampler_ = NULL;
- active_ = false;
}
#endif // ENABLE_LOGGING_AND_PROFILING
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