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// Copyright 2015 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "chrome/browser/stack_sampling_configuration.h"
#include "base/rand_util.h"
#include "chrome/browser/metrics/chrome_metrics_service_accessor.h"
#include "chrome/common/channel_info.h"
#include "components/version_info/version_info.h"
namespace {
// The profiler is currently only implemented for Windows x64, and only runs on
// trunk, canary, and dev.
bool IsProfilerSupported() {
#if !defined(_WIN64)
return false;
#else
const version_info::Channel channel = chrome::GetChannel();
return (channel == version_info::Channel::UNKNOWN ||
channel == version_info::Channel::CANARY ||
channel == version_info::Channel::DEV);
#endif
}
} // namespace
StackSamplingConfiguration::StackSamplingConfiguration()
: configuration_(GenerateConfiguration()) {
}
base::StackSamplingProfiler::SamplingParams
StackSamplingConfiguration::GetSamplingParams() const {
base::StackSamplingProfiler::SamplingParams params;
params.bursts = 1;
const base::TimeDelta duration = base::TimeDelta::FromSeconds(30);
switch (configuration_) {
case PROFILE_DISABLED:
case PROFILE_CONTROL:
params.initial_delay = base::TimeDelta::FromMilliseconds(0);
params.sampling_interval = base::TimeDelta::FromMilliseconds(0);
params.samples_per_burst = 0;
break;
case PROFILE_NO_SAMPLES:
params.initial_delay = duration;
params.sampling_interval = base::TimeDelta::FromMilliseconds(0);
params.samples_per_burst = 0;
break;
case PROFILE_5HZ:
params.initial_delay = base::TimeDelta::FromMilliseconds(0);
params.sampling_interval = base::TimeDelta::FromMilliseconds(200);
params.samples_per_burst = duration / params.sampling_interval;
break;
case PROFILE_10HZ:
params.initial_delay = base::TimeDelta::FromMilliseconds(0);
params.sampling_interval = base::TimeDelta::FromMilliseconds(100);
params.samples_per_burst = duration / params.sampling_interval;
break;
case PROFILE_100HZ:
params.initial_delay = base::TimeDelta::FromMilliseconds(0);
params.sampling_interval = base::TimeDelta::FromMilliseconds(10);
params.samples_per_burst = duration / params.sampling_interval;
break;
}
return params;
}
bool StackSamplingConfiguration::IsProfilerEnabled() const {
return (configuration_ != PROFILE_DISABLED &&
configuration_ != PROFILE_CONTROL);
}
void StackSamplingConfiguration::RegisterSyntheticFieldTrial() const {
if (!IsProfilerSupported())
return;
std::string group;
switch (configuration_) {
case PROFILE_DISABLED:
group = "Disabled";
break;
case PROFILE_CONTROL:
group = "Control";
break;
case PROFILE_NO_SAMPLES:
group = "NoSamples";
break;
case PROFILE_5HZ:
group = "5Hz";
break;
case PROFILE_10HZ:
group = "10Hz";
break;
case PROFILE_100HZ:
group = "100Hz";
break;
}
ChromeMetricsServiceAccessor::RegisterSyntheticFieldTrial(
"SyntheticStackProfilingConfiguration",
group);
}
// static
StackSamplingConfiguration::ProfileConfiguration
StackSamplingConfiguration::GenerateConfiguration() {
if (!IsProfilerSupported())
return PROFILE_DISABLED;
// Enable the profiler in the intended ultimate production configuration for
// development/waterfall builds.
if (chrome::GetChannel() == version_info::Channel::UNKNOWN)
return PROFILE_10HZ;
// Enable according to the variations below in canary and dev.
if (chrome::GetChannel() == version_info::Channel::CANARY ||
chrome::GetChannel() == version_info::Channel::DEV) {
struct Variation {
ProfileConfiguration config;
int weight;
};
// Generate a configuration according to the associated weights.
const Variation variations[] = {
{ PROFILE_10HZ, 50},
{ PROFILE_CONTROL, 50},
{ PROFILE_DISABLED, 0}
};
int total_weight = 0;
for (const Variation& variation : variations)
total_weight += variation.weight;
DCHECK_EQ(100, total_weight);
int chosen = base::RandInt(0, total_weight - 1); // Max is inclusive.
int cumulative_weight = 0;
for (const Variation& variation : variations) {
if (chosen >= cumulative_weight &&
chosen < cumulative_weight + variation.weight) {
return variation.config;
}
cumulative_weight += variation.weight;
}
NOTREACHED();
}
return PROFILE_DISABLED;
}
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