1 // Copyright 2018 The Chromium Authors 2 // Use of this source code is governed by a BSD-style license that can be 3 // found in the LICENSE file. 4 5 #ifndef BASE_TASK_TASK_FEATURES_H_ 6 #define BASE_TASK_TASK_FEATURES_H_ 7 8 #include "base/base_export.h" 9 #include "base/feature_list.h" 10 #include "base/metrics/field_trial_params.h" 11 #include "build/build_config.h" 12 13 namespace base { 14 15 // Under this feature, a utility_thread_group will be created for 16 // running USER_VISIBLE tasks. 17 BASE_EXPORT BASE_DECLARE_FEATURE(kUseUtilityThreadGroup); 18 19 // Under this feature, worker threads are not reclaimed after a timeout. Rather, 20 // only excess workers are cleaned up immediately after finishing a task. 21 BASE_EXPORT BASE_DECLARE_FEATURE(kNoWorkerThreadReclaim); 22 23 // This feature controls whether wake ups are possible for canceled tasks. 24 BASE_EXPORT BASE_DECLARE_FEATURE(kNoWakeUpsForCanceledTasks); 25 26 // Controls whether or not canceled delayed tasks are removed from task queues. 27 BASE_EXPORT BASE_DECLARE_FEATURE(kRemoveCanceledTasksInTaskQueue); 28 29 // This feature controls whether or not the scheduled task is always abandoned 30 // when a timer is stopped or reset. The re-use of the scheduled task is an 31 // optimization that ensures a timer can not leave multiple canceled tasks in 32 // the task queue. Meant to be used in conjunction with 33 // kRemoveCanceledTasksInTaskQueue. 34 BASE_EXPORT BASE_DECLARE_FEATURE(kAlwaysAbandonScheduledTask); 35 36 // This feature controls whether ThreadPool WorkerThreads should hold off waking 37 // up to purge partition alloc within the first minute of their lifetime. See 38 // base::internal::GetSleepTimeBeforePurge. 39 BASE_EXPORT BASE_DECLARE_FEATURE(kDelayFirstWorkerWake); 40 41 // Under this feature, a non-zero leeway is added to delayed tasks. Along with 42 // DelayPolicy, this affects the time at which a delayed task runs. 43 BASE_EXPORT BASE_DECLARE_FEATURE(kAddTaskLeewayFeature); 44 constexpr TimeDelta kDefaultLeeway = Milliseconds(8); 45 extern const BASE_EXPORT base::FeatureParam<TimeDelta> kTaskLeewayParam; 46 47 // Under this feature, wake ups are aligned at a 8ms boundary when allowed per 48 // DelayPolicy. 49 BASE_EXPORT BASE_DECLARE_FEATURE(kAlignWakeUps); 50 51 // Under this feature, tasks that need high resolution timer are determined 52 // based on explicit DelayPolicy rather than based on a threshold. 53 BASE_EXPORT BASE_DECLARE_FEATURE(kExplicitHighResolutionTimerWin); 54 55 // Feature to run tasks by batches before pumping out messages. 56 BASE_EXPORT BASE_DECLARE_FEATURE(kRunTasksByBatches); 57 58 BASE_EXPORT void InitializeTaskLeeway(); 59 BASE_EXPORT TimeDelta GetTaskLeewayForCurrentThread(); 60 BASE_EXPORT TimeDelta GetDefaultTaskLeeway(); 61 62 // Controls the max number of delayed tasks that can run before selecting an 63 // immediate task in sequence manager. 64 BASE_EXPORT BASE_DECLARE_FEATURE(kMaxDelayedStarvationTasks); 65 extern const BASE_EXPORT base::FeatureParam<int> 66 kMaxDelayedStarvationTasksParam; 67 68 } // namespace base 69 70 #endif // BASE_TASK_TASK_FEATURES_H_ 71