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/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at */
include protocol PBackground;
using mozilla::TimeDuration from "mozilla/TimeStamp.h";
[MoveOnly] using base::SharedMemoryHandle from "base/shared_memory.h";
namespace mozilla {
namespace ipc {
* PIdleScheduler is the protocol for cross-process idle scheduling.
* Only child processes participate in the scheduling and parent process
* can run its idle tasks whenever it needs to.
* The scheduler keeps track of the following things.
* - Activity of the main thread of each child process. A process is active
* when it is running tasks. Because of performance cross-process
* counters in shared memory are used for the activity tracking. There is
* one counter counting the activity state of all the processes and one
* counter for each process. This way if a child process crashes, the global
* counter can be updated by decrementing the per process counter from it.
* - Child processes running prioritized operation. Top level page loads is an
* example of a prioritized operation. When such is ongoing, idle tasks are
* less likely to run.
* - Idle requests. When a child process locally has idle tasks to run, it
* requests idle time from the scheduler. Initially requests go to a wait list
* and the scheduler runs and if there are free logical cores for the child
* processes, idle time is given to the child process, and the process goes to
* the idle list. Once idle time has been consumed or there are no tasks to
* process, child process informs the scheduler and the process is moved back
* to the default queue.
async protocol PIdleScheduler
manager PBackground;
async IdleTime(uint64_t id, TimeDuration budget);
async InitForIdleUse() returns (SharedMemoryHandle? state, uint32_t childId);
async RequestIdleTime(uint64_t id, TimeDuration budget);
async IdleTimeUsed(uint64_t id);
// Child can send explicit Schedule message to parent if it thinks parent process
// might be able to let some other process to use idle time.
async Schedule();
// Note, these two messages can be sent even before InitForIdleUse.
async RunningPrioritizedOperation();
async PrioritizedOperationDone();
// Ask if now would be a good time to GC
async RequestGC() returns (bool may_gc);
// Let the parent know when we start a GC without asking first.
async StartedGC();
// Called for ending any kind of GC.
async DoneGC();
// This message is never sent. Each PIdleScheduler actor will stay alive as long as
// its PBackground manager.
async __delete__();
} // namespace ipc
} // namespace mozilla