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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.
#ifndef CHROME_COMMON_PROFILER_STACK_SAMPLING_CONFIGURATION_H_
#define CHROME_COMMON_PROFILER_STACK_SAMPLING_CONFIGURATION_H_
#include <string>
#include "base/callback.h"
#include "base/macros.h"
#include "base/profiler/stack_sampling_profiler.h"
namespace base {
class CommandLine;
} // namespace base
// StackSamplingConfiguration chooses a configuration for the enable state of
// the stack sampling profiler across all processes. This configuration is
// determined once at browser process startup. Configurations for child
// processes are communicated via command line arguments.
class StackSamplingConfiguration {
public:
StackSamplingConfiguration();
// Get the stack sampling params to use.
base::StackSamplingProfiler::SamplingParams GetSamplingParams() const;
// Returns true if the profiler should be started for the current process.
bool IsProfilerEnabledForCurrentProcess() const;
// Get the synthetic field trial configuration. Returns true if a synthetic
// field trial should be registered. This should only be called from the
// browser process. When run at startup, the profiler must use a synthetic
// field trial since it runs before the metrics field trials are initialized.
bool GetSyntheticFieldTrial(std::string* trial_name,
std::string* group_name) const;
// Add a command line switch that instructs the child process to run the
// profiler. This should only be called from the browser process.
void AppendCommandLineSwitchForChildProcess(
const std::string& process_type,
base::CommandLine* command_line) const;
// Returns the StackSamplingConfiguration for the process.
static StackSamplingConfiguration* Get();
private:
// Configuration to use for this Chrome instance.
enum ProfileConfiguration {
// Chrome-wide configurations set in the browser process.
PROFILE_DISABLED,
PROFILE_DISABLED_TREND_MICRO,
PROFILE_CONTROL,
PROFILE_ENABLED,
// Configuration set in the child processes, which receive their enable
// state on the command line from the browser process.
PROFILE_FROM_COMMAND_LINE
};
// Configuration variations, along with weights to use when randomly choosing
// one of a set of variations.
struct Variation {
ProfileConfiguration config;
int weight;
};
// Randomly chooses a configuration from the weighted variations. Weights are
// expected to sum to 100 as a sanity check.
static ProfileConfiguration ChooseConfiguration(
const std::vector<Variation>& variations);
// Generates sampling profiler configurations for all processes.
static ProfileConfiguration GenerateConfiguration();
// NOTE: all state in this class must be const and initialized at construction
// time to ensure thread-safe access post-construction.
// In the browser process this represents the configuration to use across all
// Chrome processes. In the child processes it is always
// PROFILE_FROM_COMMAND_LINE.
const ProfileConfiguration configuration_;
DISALLOW_COPY_AND_ASSIGN(StackSamplingConfiguration);
};
#endif // CHROME_COMMON_PROFILER_STACK_SAMPLING_CONFIGURATION_H_