Revision: 16564
Author: [email protected]
Date: Fri Sep 6 06:25:06 2013 UTC
Log: Check if timeout has expired after processing each sample
To avoid long intervals between taking samples due to processing all
accumulated samples at once, the samples are processed one by one and we
check if the sampling interval has elapsed after each step rather than
after processing all the samples in the queue.
This is a modified version of r16549 whith a fix for test flakiness. The
test flakiness introduced by the previous version of this changed was fixed
by changing return type of ProfilerEventsProcessor::ProcessOneSample from
bool to enum with 3 options. In the main profiling loop we decide that the
next code event should be processed when sample with a greater ordinal
number is encountered. When processing remaining samples we shouldn't wait
for more samples and if the samples queue is empty we just process next
code event.
BUG=v8:2814,v8:2871
[email protected], [email protected]
Review URL: https://codereview.chromium.org/23455036
http://code.google.com/p/v8/source/detail?r=16564
Modified:
/branches/bleeding_edge/src/cpu-profiler.cc
/branches/bleeding_edge/src/cpu-profiler.h
=======================================
--- /branches/bleeding_edge/src/cpu-profiler.cc Thu Sep 5 13:20:51 2013 UTC
+++ /branches/bleeding_edge/src/cpu-profiler.cc Fri Sep 6 06:25:06 2013 UTC
@@ -103,50 +103,54 @@
return false;
}
-
-bool ProfilerEventsProcessor::ProcessTicks() {
- while (true) {
- while (!ticks_from_vm_buffer_.IsEmpty()
- && ticks_from_vm_buffer_.Peek()->order ==
- last_processed_code_event_id_) {
- TickSampleEventRecord record;
- ticks_from_vm_buffer_.Dequeue(&record);
- generator_->RecordTickSample(record.sample);
- }
-
- const TickSampleEventRecord* record = ticks_buffer_.Peek();
- if (record == NULL) return !ticks_from_vm_buffer_.IsEmpty();
- if (record->order != last_processed_code_event_id_) return true;
- generator_->RecordTickSample(record->sample);
- ticks_buffer_.Remove();
+ProfilerEventsProcessor::SampleProcessingResult
+ ProfilerEventsProcessor::ProcessOneSample() {
+ if (!ticks_from_vm_buffer_.IsEmpty()
+ && ticks_from_vm_buffer_.Peek()->order ==
+ last_processed_code_event_id_) {
+ TickSampleEventRecord record;
+ ticks_from_vm_buffer_.Dequeue(&record);
+ generator_->RecordTickSample(record.sample);
+ return OneSampleProcessed;
}
-}
-
-void ProfilerEventsProcessor::ProcessEventsAndDoSample() {
- ElapsedTimer timer;
- timer.Start();
- // Keep processing existing events until we need to do next sample.
- while (!timer.HasExpired(period_)) {
- if (ProcessTicks()) {
- // All ticks of the current dequeue_order are processed,
- // proceed to the next code event.
- ProcessCodeEvent();
- }
+ const TickSampleEventRecord* record = ticks_buffer_.Peek();
+ if (record == NULL) {
+ if (ticks_from_vm_buffer_.IsEmpty()) return NoSamplesInQueue;
+ return FoundSampleForNextCodeEvent;
}
- // Schedule next sample. sampler_ is NULL in tests.
- if (sampler_) sampler_->DoSample();
+ if (record->order != last_processed_code_event_id_) {
+ return FoundSampleForNextCodeEvent;
+ }
+ generator_->RecordTickSample(record->sample);
+ ticks_buffer_.Remove();
+ return OneSampleProcessed;
}
void ProfilerEventsProcessor::Run() {
while (running_) {
- ProcessEventsAndDoSample();
+ ElapsedTimer timer;
+ timer.Start();
+ // Keep processing existing events until we need to do next sample.
+ do {
+ if (FoundSampleForNextCodeEvent == ProcessOneSample()) {
+ // All ticks of the current last_processed_code_event_id_ are
+ // processed, proceed to the next code event.
+ ProcessCodeEvent();
+ }
+ } while (!timer.HasExpired(period_));
+
+ // Schedule next sample. sampler_ is NULL in tests.
+ if (sampler_) sampler_->DoSample();
}
// Process remaining tick events.
do {
- ProcessTicks();
+ SampleProcessingResult result;
+ do {
+ result = ProcessOneSample();
+ } while (result == OneSampleProcessed);
} while (ProcessCodeEvent());
}
=======================================
--- /branches/bleeding_edge/src/cpu-profiler.h Thu Sep 5 12:17:17 2013 UTC
+++ /branches/bleeding_edge/src/cpu-profiler.h Fri Sep 6 06:25:06 2013 UTC
@@ -161,9 +161,13 @@
private:
// Called from events processing thread (Run() method.)
bool ProcessCodeEvent();
- bool ProcessTicks();
- void ProcessEventsAndDoSample();
+ enum SampleProcessingResult {
+ OneSampleProcessed,
+ FoundSampleForNextCodeEvent,
+ NoSamplesInQueue
+ };
+ SampleProcessingResult ProcessOneSample();
ProfileGenerator* generator_;
Sampler* sampler_;
--
--
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