92 lines
3.2 KiB
C++
92 lines
3.2 KiB
C++
// Copyright 2018 The Chromium Authors
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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/task_features.h"
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#include <atomic>
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#include "base/base_export.h"
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#include "base/feature_list.h"
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#include "base/threading/platform_thread.h"
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namespace base {
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// Note to implementers: thread pool code using task features must absolutely
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// not invoke FeatureList::IsEnabled outside of the main thread. Doing so
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// causes data races between worker threads and ~FeatureList when tests end
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// (crbug.com/1344573). A reliable moment to query and cache the feature state
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// is on ThreadPoolImpl::Start (and thus also on the first WorkerThread::Start,
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// not the later ones) as this is invoked from the main thread after
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// initializing the FeatureList. If caching the feature state in a static, you
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// must be aware that all tests sharing a process will have the same state,
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// regardless of future ScopedFeatureList instances.
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BASE_FEATURE(kUseUtilityThreadGroup,
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"UseUtilityThreadGroup",
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base::FEATURE_DISABLED_BY_DEFAULT);
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BASE_FEATURE(kNoWorkerThreadReclaim,
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"NoWorkerThreadReclaim",
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base::FEATURE_ENABLED_BY_DEFAULT);
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// static
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BASE_FEATURE(kNoWakeUpsForCanceledTasks,
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"NoWakeUpsForCanceledTasks",
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FEATURE_ENABLED_BY_DEFAULT);
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BASE_FEATURE(kRemoveCanceledTasksInTaskQueue,
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"RemoveCanceledTasksInTaskQueue2",
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base::FEATURE_ENABLED_BY_DEFAULT);
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BASE_FEATURE(kDelayFirstWorkerWake,
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"DelayFirstWorkerWake",
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base::FEATURE_DISABLED_BY_DEFAULT);
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BASE_FEATURE(kAddTaskLeewayFeature,
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"AddTaskLeeway",
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base::FEATURE_ENABLED_BY_DEFAULT);
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const base::FeatureParam<TimeDelta> kTaskLeewayParam{&kAddTaskLeewayFeature,
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"leeway", kDefaultLeeway};
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BASE_FEATURE(kAlignWakeUps, "AlignWakeUps", base::FEATURE_ENABLED_BY_DEFAULT);
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BASE_FEATURE(kExplicitHighResolutionTimerWin,
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"ExplicitHighResolutionTimerWin",
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base::FEATURE_DISABLED_BY_DEFAULT);
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BASE_FEATURE(kRunTasksByBatches,
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"RunTasksByBatches",
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base::FEATURE_DISABLED_BY_DEFAULT);
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// Leeway value applied to delayed tasks. An atomic is used here because the
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// value is queried from multiple threads.
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std::atomic<TimeDelta> g_task_leeway{kDefaultLeeway};
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BASE_EXPORT void InitializeTaskLeeway() {
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g_task_leeway.store(kTaskLeewayParam.Get(), std::memory_order_relaxed);
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}
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BASE_EXPORT TimeDelta GetTaskLeewayForCurrentThread() {
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// For some threads, there might be a override of the leeway, so check it
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// first.
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auto leeway_override = PlatformThread::GetThreadLeewayOverride();
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if (leeway_override.has_value())
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return leeway_override.value();
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return g_task_leeway.load(std::memory_order_relaxed);
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}
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BASE_EXPORT TimeDelta GetDefaultTaskLeeway() {
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return g_task_leeway.load(std::memory_order_relaxed);
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}
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BASE_FEATURE(kMaxDelayedStarvationTasks,
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"MaxDelayedStarvationTasks",
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base::FEATURE_ENABLED_BY_DEFAULT);
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const base::FeatureParam<int> kMaxDelayedStarvationTasksParam{
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&kMaxDelayedStarvationTasks, "count", 3};
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} // namespace base
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