deps: don't busy loop in v8 cpu profiler thread

Backport 6964a9e0685fa186d9d9b7907be17505e839db1a from upstream v8.

Original commit message:

  Make CPU profiler do not hog 100% of CPU.

  Tick event processor should not stay in a tight loop
  when there's nothing to do. It can go sleep until next sample event.

  LOG=N
  BUG=v8:3967
  Committed: https://crrev.com/6964a9e0685fa186d9d9b7907be17505e839db1a
  Cr-Commit-Position: refs/heads/master@{#28211}

Fixes #25137
Related: #9439, #8789

PR: #25268
PR-URL: https://github.com/joyent/node/pull/25268
Reviewed-By: Michael Dawson <michael_dawson@ca.ibm.com>
Reviewed-By: Julien Gilli <jgilli@fastmail.fm>

10 files changed, 40 insertions, 22 deletions

diff --git a/deps/v8/src/base/platform/platform-posix.cc b/deps/v8/src/base/platform/platform-posix.cc
index 771634e24e..f3b42d0b00 100644
--- a/deps/v8/src/base/platform/platform-posix.cc
+++ b/deps/v8/src/base/platform/platform-posix.cc
@@ -268,9 +268,8 @@ size_t OS::AllocateAlignment() {
 }
 
 
-void OS::Sleep(int milliseconds) {
-  useconds_t ms = static_cast<useconds_t>(milliseconds);
-  usleep(1000 * ms);
+void OS::Sleep(TimeDelta interval) {
+  usleep(static_cast<useconds_t>(interval.InMicroseconds()));
 }
 
 
diff --git a/deps/v8/src/base/platform/platform-win32.cc b/deps/v8/src/base/platform/platform-win32.cc
index 9f106785eb..f18bb99237 100644
--- a/deps/v8/src/base/platform/platform-win32.cc
+++ b/deps/v8/src/base/platform/platform-win32.cc
@@ -821,8 +821,8 @@ void OS::Guard(void* address, const size_t size) {
 }
 
 
-void OS::Sleep(int milliseconds) {
-  ::Sleep(milliseconds);
+void OS::Sleep(TimeDelta interval) {
+  ::Sleep(static_cast<DWORD>(interval.InMilliseconds()));
 }
 
 
diff --git a/deps/v8/src/base/platform/platform.h b/deps/v8/src/base/platform/platform.h
index 9567572d80..40ef8b85a0 100644
--- a/deps/v8/src/base/platform/platform.h
+++ b/deps/v8/src/base/platform/platform.h
@@ -227,8 +227,8 @@ class OS {
   // Get the Alignment guaranteed by Allocate().
   static size_t AllocateAlignment();
 
-  // Sleep for a number of milliseconds.
-  static void Sleep(const int milliseconds);
+  // Sleep for a specified time interval.
+  static void Sleep(TimeDelta interval);
 
   // Abort the current process.
   static void Abort();
diff --git a/deps/v8/src/cpu-profiler.cc b/deps/v8/src/cpu-profiler.cc
index 68a565c73a..f53afdd252 100644
--- a/deps/v8/src/cpu-profiler.cc
+++ b/deps/v8/src/cpu-profiler.cc
@@ -108,16 +108,32 @@ ProfilerEventsProcessor::SampleProcessingResult
 
 void ProfilerEventsProcessor::Run() {
   while (running_) {
-    base::ElapsedTimer timer;
-    timer.Start();
-    // Keep processing existing events until we need to do next sample.
+    base::TimeTicks nextSampleTime =
+        base::TimeTicks::HighResolutionNow() + period_;
+    base::TimeTicks now;
+    SampleProcessingResult result;
+    // Keep processing existing events until we need to do next sample
+    // or the ticks buffer is empty.
     do {
-      if (FoundSampleForNextCodeEvent == ProcessOneSample()) {
+      result = ProcessOneSample();
+      if (result == FoundSampleForNextCodeEvent) {
         // All ticks of the current last_processed_code_event_id_ are
         // processed, proceed to the next code event.
         ProcessCodeEvent();
       }
-    } while (!timer.HasExpired(period_));
+      now = base::TimeTicks::HighResolutionNow();
+    } while (result != NoSamplesInQueue && now < nextSampleTime);
+
+    if (nextSampleTime > now) {
+#if V8_OS_WIN
+      // Do not use Sleep on Windows as it is very imprecise.
+      // Could be up to 16ms jitter, which is unacceptable for the purpose.
+      while (base::TimeTicks::HighResolutionNow() < nextSampleTime) {
+      }
+#else
+      base::OS::Sleep(nextSampleTime - now);
+#endif
+    }
 
     // Schedule next sample. sampler_ is NULL in tests.
     if (sampler_) sampler_->DoSample();
diff --git a/deps/v8/src/optimizing-compiler-thread.cc b/deps/v8/src/optimizing-compiler-thread.cc
index 0074adbefe..c9bc538d65 100644
--- a/deps/v8/src/optimizing-compiler-thread.cc
+++ b/deps/v8/src/optimizing-compiler-thread.cc
@@ -48,7 +48,8 @@ void OptimizingCompilerThread::Run() {
     TimerEventScope<TimerEventRecompileConcurrent> timer(isolate_);
 
     if (FLAG_concurrent_recompilation_delay != 0) {
-      base::OS::Sleep(FLAG_concurrent_recompilation_delay);
+      base::OS::Sleep(base::TimeDelta::FromMilliseconds(
+          FLAG_concurrent_recompilation_delay));
     }
 
     switch (static_cast<StopFlag>(base::Acquire_Load(&stop_thread_))) {
diff --git a/deps/v8/src/runtime.cc b/deps/v8/src/runtime.cc
index d29c861017..7191ac0b8a 100644
--- a/deps/v8/src/runtime.cc
+++ b/deps/v8/src/runtime.cc
@@ -8641,7 +8641,7 @@ RUNTIME_FUNCTION(Runtime_GetOptimizationStatus) {
       sync_with_compiler_thread) {
     while (function->IsInOptimizationQueue()) {
       isolate->optimizing_compiler_thread()->InstallOptimizedFunctions();
-      base::OS::Sleep(50);
+      base::OS::Sleep(base::TimeDelta::FromMilliseconds(50));
     }
   }
   if (FLAG_always_opt) {
diff --git a/deps/v8/src/sampler.cc b/deps/v8/src/sampler.cc
index 413b6be906..0be31b51b0 100644
--- a/deps/v8/src/sampler.cc
+++ b/deps/v8/src/sampler.cc
@@ -550,7 +550,7 @@ class SamplerThread : public base::Thread {
           sampler->DoSample();
         }
       }
-      base::OS::Sleep(interval_);
+      base::OS::Sleep(base::TimeDelta::FromMilliseconds(interval_));
     }
   }
 
diff --git a/deps/v8/test/cctest/test-api.cc b/deps/v8/test/cctest/test-api.cc
index 2ac657d7f9..9666a10fd7 100644
--- a/deps/v8/test/cctest/test-api.cc
+++ b/deps/v8/test/cctest/test-api.cc
@@ -15166,10 +15166,12 @@ class RegExpInterruptionThread : public v8::base::Thread {
     for (regexp_interruption_data.loop_count = 0;
          regexp_interruption_data.loop_count < 7;
          regexp_interruption_data.loop_count++) {
-      v8::base::OS::Sleep(50);  // Wait a bit before requesting GC.
+      // Wait a bit before requesting GC.
+      v8::base::OS::Sleep(v8::base::TimeDelta::FromMilliseconds(50));
       reinterpret_cast<i::Isolate*>(isolate_)->stack_guard()->RequestGC();
     }
-    v8::base::OS::Sleep(50);  // Wait a bit before terminating.
+    // Wait a bit before terminating.
+    v8::base::OS::Sleep(v8::base::TimeDelta::FromMilliseconds(50));
     v8::V8::TerminateExecution(isolate_);
   }
 
@@ -21516,7 +21518,7 @@ class ThreadInterruptTest {
       struct sigaction action;
 
       // Ensure that we'll enter waiting condition
-      v8::base::OS::Sleep(100);
+      v8::base::OS::Sleep(v8::base::TimeDelta::FromMilliseconds(100));
 
       // Setup signal handler
       memset(&action, 0, sizeof(action));
@@ -21527,7 +21529,7 @@ class ThreadInterruptTest {
       kill(getpid(), SIGCHLD);
 
       // Ensure that if wait has returned because of error
-      v8::base::OS::Sleep(100);
+      v8::base::OS::Sleep(v8::base::TimeDelta::FromMilliseconds(100));
 
       // Set value and signal semaphore
       test_->sem_value_ = 1;
diff --git a/deps/v8/test/cctest/test-cpu-profiler.cc b/deps/v8/test/cctest/test-cpu-profiler.cc
index 6051c3fd7f..8536c9b12e 100644
--- a/deps/v8/test/cctest/test-cpu-profiler.cc
+++ b/deps/v8/test/cctest/test-cpu-profiler.cc
@@ -793,7 +793,7 @@ class TestApiCallbacks {
     double start = v8::base::OS::TimeCurrentMillis();
     double duration = 0;
     while (duration < min_duration_ms_) {
-      v8::base::OS::Sleep(1);
+      v8::base::OS::Sleep(v8::base::TimeDelta::FromMilliseconds(1));
       duration = v8::base::OS::TimeCurrentMillis() - start;
     }
   }
diff --git a/deps/v8/test/cctest/test-log.cc b/deps/v8/test/cctest/test-log.cc
index 6800215081..0999e53877 100644
--- a/deps/v8/test/cctest/test-log.cc
+++ b/deps/v8/test/cctest/test-log.cc
@@ -186,7 +186,7 @@ class LoopingJsThread : public LoopingThread {
             "var j; for (var i=0; i<10000; ++i) { j = Math.sin(i); }");
       }
       context.Dispose();
-      i::OS::Sleep(1);
+      i::OS::Sleep(v8::base::TimeDelta::FromMilliseconds(1));
     }
   }
 };
@@ -206,7 +206,7 @@ class LoopingNonJsThread : public LoopingThread {
     SignalRunning();
     while (IsRunning()) {
       i = std::sin(i);
-      i::OS::Sleep(1);
+      i::OS::Sleep(v8::base::TimeDelta::FromMilliseconds(1));
     }
   }
 };