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94 lines
3.5 KiB
94 lines
3.5 KiB
// Copyright 2018 The Chromium Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style license that can be
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// found in the LICENSE file.
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#include "base/task_scheduler/service_thread.h"
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#include "base/bind.h"
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#include "base/bind_helpers.h"
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#include "base/debug/alias.h"
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#include "base/rand_util.h"
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#include "base/stl_util.h"
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#include "base/task_scheduler/post_task.h"
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#include "base/task_scheduler/task_scheduler.h"
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#include "base/task_scheduler/task_tracker.h"
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#include "base/task_scheduler/task_traits.h"
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#include "build/build_config.h"
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namespace base {
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namespace internal {
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namespace {
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TimeDelta g_heartbeat_for_testing = TimeDelta();
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} // namespace
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ServiceThread::ServiceThread(const TaskTracker* task_tracker)
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: Thread("TaskSchedulerServiceThread"), task_tracker_(task_tracker) {}
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// static
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void ServiceThread::SetHeartbeatIntervalForTesting(TimeDelta heartbeat) {
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g_heartbeat_for_testing = heartbeat;
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}
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void ServiceThread::Init() {
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// In unit tests we sometimes do not have a fully functional TaskScheduler
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// environment, do not perform the heartbeat report in that case since it
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// relies on such an environment.
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if (task_tracker_ && TaskScheduler::GetInstance()) {
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// Seemingly causing power regression on Android, disable to see if truly at
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// fault : https://crbug.com/848255
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#if !defined(OS_ANDROID)
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// Compute the histogram every hour (with a slight offset to drift if that
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// hour tick happens to line up with specific events). Once per hour per
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// user was deemed sufficient to gather a reliable metric.
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constexpr TimeDelta kHeartbeat = TimeDelta::FromMinutes(59);
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heartbeat_latency_timer_.Start(
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FROM_HERE,
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g_heartbeat_for_testing.is_zero() ? kHeartbeat
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: g_heartbeat_for_testing,
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BindRepeating(&ServiceThread::PerformHeartbeatLatencyReport,
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Unretained(this)));
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#endif
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}
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}
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NOINLINE void ServiceThread::Run(RunLoop* run_loop) {
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const int line_number = __LINE__;
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Thread::Run(run_loop);
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base::debug::Alias(&line_number);
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}
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void ServiceThread::PerformHeartbeatLatencyReport() const {
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static constexpr TaskTraits kReportedTraits[] = {
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{TaskPriority::BACKGROUND}, {TaskPriority::BACKGROUND, MayBlock()},
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{TaskPriority::USER_VISIBLE}, {TaskPriority::USER_VISIBLE, MayBlock()},
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{TaskPriority::USER_BLOCKING}, {TaskPriority::USER_BLOCKING, MayBlock()}};
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// Only record latency for one set of TaskTraits per report to avoid bias in
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// the order in which tasks are posted (should we record all at once) as well
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// as to avoid spinning up many worker threads to process this report if the
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// scheduler is currently idle (each pool keeps at least one idle thread so a
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// single task isn't an issue).
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// Invoke RandInt() out-of-line to ensure it's obtained before
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// TimeTicks::Now().
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const TaskTraits& profiled_traits =
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kReportedTraits[RandInt(0, base::size(kReportedTraits) - 1)];
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// Post through the static API to time the full stack. Use a new Now() for
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// every set of traits in case PostTaskWithTraits() itself is slow.
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// Bonus: this appraoch also includes the overhead of Bind() in the reported
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// latency).
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base::PostTaskWithTraits(
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FROM_HERE, profiled_traits,
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BindOnce(&TaskTracker::RecordLatencyHistogram, Unretained(task_tracker_),
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TaskTracker::LatencyHistogramType::HEARTBEAT_LATENCY,
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profiled_traits, TimeTicks::Now()));
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}
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} // namespace internal
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} // namespace base
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