flutter::SamplingProfiler Class Reference

a Sampling Profiler that runs peridically and calls the Sampler which servers as a value function to gather various profiling metrics as represented by ProfileSample. These profiling metrics are then posted to the Dart VM Service timeline. More...

#include <sampling_profiler.h>

Public Member Functions
	SamplingProfiler (const char *thread_label, fml::RefPtr< fml::TaskRunner > profiler_task_runner, Sampler sampler, int num_samples_per_sec)
	Construct a new Sampling Profiler object. More...
	~SamplingProfiler ()
void	Start ()
	Starts the SamplingProfiler by triggering SampleRepeatedly. More...
void	Stop ()

Detailed Description

a Sampling Profiler that runs peridically and calls the Sampler which servers as a value function to gather various profiling metrics as represented by ProfileSample. These profiling metrics are then posted to the Dart VM Service timeline.

Definition at line 82 of file sampling_profiler.h.

Constructor & Destructor Documentation

SamplingProfiler()

flutter::SamplingProfiler::SamplingProfiler	(	const char *	thread_label,
		fml::RefPtr< fml::TaskRunner >	profiler_task_runner,
		Sampler	sampler,
		int	num_samples_per_sec
	)

Construct a new Sampling Profiler object.

Parameters

thread_label	Dart VM Service prefix to be set for the profiling task runner.
profiler_task_runner	the task runner to service sampling requests.
sampler	the value function to collect the profiling metrics.
num_samples_per_sec	number of times you wish to run the sampler per second.

See also

fml::TaskRunner

Definition at line 11 of file sampling_profiler.cc.

    : thread_label_(thread_label),
      profiler_task_runner_(std::move(profiler_task_runner)),
      sampler_(std::move(sampler)),
      num_samples_per_sec_(num_samples_per_sec) {}

~SamplingProfiler()

flutter::SamplingProfiler::~SamplingProfiler

(

)

Definition at line 21 of file sampling_profiler.cc.

                                    {
  if (is_running_) {
    Stop();
  }
}

Member Function Documentation

Start()

void flutter::SamplingProfiler::Start

(

)

Starts the SamplingProfiler by triggering SampleRepeatedly.

Definition at line 27 of file sampling_profiler.cc.

                             {
  if (!profiler_task_runner_) {
    return;
  }
  FML_CHECK(num_samples_per_sec_ > 0)
      << "number of samples must be a positive integer, got: "
      << num_samples_per_sec_;
  double delay_between_samples = 1.0 / num_samples_per_sec_;
  auto task_delay = fml::TimeDelta::FromSecondsF(delay_between_samples);
  UpdateDartVMServiceThreadName();
  is_running_ = true;
  SampleRepeatedly(task_delay);
}

Stop()

void flutter::SamplingProfiler::Stop

(

)

Definition at line 41 of file sampling_profiler.cc.

                            {
  FML_DCHECK(is_running_);
  auto latch = std::make_unique<fml::AutoResetWaitableEvent>();
  shutdown_latch_.store(latch.get());
  latch->Wait();
  shutdown_latch_.store(nullptr);
  is_running_ = false;
}

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The documentation for this class was generated from the following files:

• shell/profiling/sampling_profiler.h
• shell/profiling/sampling_profiler.cc