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// Copyright 2023 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifndef COMPONENTS_STARTUP_METRIC_UTILS_COMMON_STARTUP_METRIC_UTILS_H_
#define COMPONENTS_STARTUP_METRIC_UTILS_COMMON_STARTUP_METRIC_UTILS_H_
#include <string_view>
#include "base/component_export.h"
#include "base/containers/flat_set.h"
#include "base/dcheck_is_on.h"
#include "base/location.h"
#include "base/notreached.h"
#include "base/time/time.h"
// Utility functions to support metric collection for startup common across
// processes. Timings should use TimeTicks whenever possible. OS-provided
// timings are still received as Time out of cross-platform support necessity
// but are converted to TimeTicks as soon as possible in an attempt to reduce
// the potential skew between the two basis. See crbug.com/544131 for reasoning.
namespace startup_metric_utils {
class BrowserStartupMetricRecorder;
class GpuStartupMetricRecorder;
class RendererStartupMetricRecorder;
class COMPONENT_EXPORT(STARTUP_METRIC_UTILS) CommonStartupMetricRecorder final {
public:
// Call this with the creation time of the startup (initial/main) process.
void RecordStartupProcessCreationTime(base::Time time);
void RecordStartupProcessCreationTime(base::TimeTicks ticks);
// Call this with a time recorded as early as possible in the startup process.
// On Android, the application start is the time at which the Java code
// starts. On Windows, the application start is sampled from chrome.exe:main,
// before chrome.dll is loaded.
void RecordApplicationStartTime(base::TimeTicks ticks);
// Call this with the time when the executable is loaded and the ChromeMain()
// function is invoked.
void RecordChromeMainEntryTime(base::TimeTicks ticks);
// Call this with the time immediately before/after base::PreReadFile() is
// called on the main DLL on startup.
void RecordPreReadTime(base::TimeTicks start_ticks,
base::TimeTicks end_ticks);
// Returns the TimeTicks corresponding to main entry as recorded by
// |RecordMainEntryPointTime|. Returns a null TimeTicks if a value has not
// been recorded yet. This method is expected to be called from the UI
// thread.
base::TimeTicks MainEntryPointTicks() const;
private:
friend class BrowserStartupMetricRecorder;
friend class GpuStartupMetricRecorder;
friend class RendererStartupMetricRecorder;
friend COMPONENT_EXPORT(STARTUP_METRIC_UTILS)
CommonStartupMetricRecorder& GetCommon();
// Only permit construction from within GetCommon().
CommonStartupMetricRecorder() = default;
// Converts a base::Time value to a base::TimeTicks value. The conversion
// isn't exact, but by capturing Time::Now() as early as possible, the
// likelihood of a clock change between it and process start is as low as
// possible. There is also the time taken to synchronously resolve
// base::Time::Now() and base::TimeTicks::Now() at play, but in practice it is
// pretty much instant compared to multi-seconds startup timings.
base::TimeTicks StartupTimeToTimeTicks(base::Time time);
void AddStartupEventsForTelemetry();
// Call BrowserStartupMetricRecorder::ResetSessionForTesting.
void ResetSessionForTesting();
#if DCHECK_IS_ON()
base::flat_set<const void*>& GetSessionLog();
#endif // DCHECK_IS_ON()
// DCHECKs that this is the first time |method_id| is passed to this assertion
// in this session (a session is typically process-lifetime but this can be
// reset in tests via ResetSessionForTesting()). Callers should use FROM_HERE
// as a unique id.
void AssertFirstCallInSession(base::Location from_here);
// Common helper to report "startup" category trace events as well as a
// histogram of the same name. Example call:
// EmitHistogramWithTraceEvent(
// &base::UmaHistogramLongTimes,
// "Startup.LoadTime.ApplicationStartToChromeMain",
// GetCommon().application_start_ticks_,
// GetCommon().chrome_main_entry_ticks_);
using HistogramTimeFunction = void(std::string_view name, base::TimeDelta);
void EmitHistogramWithTraceEvent(HistogramTimeFunction* histogram_function,
const char* name,
base::TimeTicks begin_ticks,
base::TimeTicks end_ticks);
// Emit a "startup" category event.
void EmitTraceEvent(const char* name,
base::TimeTicks begin_ticks,
base::TimeTicks end_ticks);
// Emit info to the "startup" category in the form of an instant event.
void EmitInstantEvent(const char* name);
base::TimeTicks process_creation_ticks_;
base::TimeTicks application_start_ticks_;
base::TimeTicks chrome_main_entry_ticks_;
base::TimeTicks preread_begin_ticks_;
base::TimeTicks preread_end_ticks_;
};
COMPONENT_EXPORT(STARTUP_METRIC_UTILS)
CommonStartupMetricRecorder& GetCommon();
} // namespace startup_metric_utils
#endif // COMPONENTS_STARTUP_METRIC_UTILS_COMMON_STARTUP_METRIC_UTILS_H_
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