gecko-dev/xpcom/threads/MainThreadIdlePeriod.cpp

102 строки
3.0 KiB
C++

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
/* vim: set ts=8 sts=2 et sw=2 tw=80: */
/* 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 http://mozilla.org/MPL/2.0/. */
#include "MainThreadIdlePeriod.h"
#include "mozilla/Maybe.h"
#include "mozilla/Preferences.h"
#include "nsRefreshDriver.h"
#include "nsThreadUtils.h"
#define DEFAULT_LONG_IDLE_PERIOD 50.0f
#define DEFAULT_MIN_IDLE_PERIOD 3.0f
#define DEFAULT_MAX_TIMER_THREAD_BOUND 5
const uint32_t kMaxTimerThreadBoundClamp = 15;
namespace mozilla {
NS_IMETHODIMP
MainThreadIdlePeriod::GetIdlePeriodHint(TimeStamp* aIdleDeadline)
{
MOZ_ASSERT(NS_IsMainThread());
MOZ_ASSERT(aIdleDeadline);
TimeStamp now = TimeStamp::Now();
TimeStamp currentGuess =
now + TimeDuration::FromMilliseconds(GetLongIdlePeriod());
currentGuess = nsRefreshDriver::GetIdleDeadlineHint(currentGuess);
currentGuess = NS_GetTimerDeadlineHintOnCurrentThread(currentGuess, GetMaxTimerThreadBound());
// If the idle period is too small, then just return a null time
// to indicate we are busy. Otherwise return the actual deadline.
TimeDuration minIdlePeriod =
TimeDuration::FromMilliseconds(GetMinIdlePeriod());
bool busySoon = currentGuess.IsNull() ||
(now >= (currentGuess - minIdlePeriod)) ||
currentGuess < mLastIdleDeadline;
if (!busySoon) {
*aIdleDeadline = mLastIdleDeadline = currentGuess;
}
return NS_OK;
}
/* static */ float
MainThreadIdlePeriod::GetLongIdlePeriod()
{
MOZ_ASSERT(NS_IsMainThread());
static float sLongIdlePeriod = DEFAULT_LONG_IDLE_PERIOD;
static bool sInitialized = false;
if (!sInitialized && Preferences::IsServiceAvailable()) {
sInitialized = true;
Preferences::AddFloatVarCache(&sLongIdlePeriod, "idle_queue.long_period",
DEFAULT_LONG_IDLE_PERIOD);
}
return sLongIdlePeriod;
}
/* static */ float
MainThreadIdlePeriod::GetMinIdlePeriod()
{
MOZ_ASSERT(NS_IsMainThread());
static float sMinIdlePeriod = DEFAULT_MIN_IDLE_PERIOD;
static bool sInitialized = false;
if (!sInitialized && Preferences::IsServiceAvailable()) {
sInitialized = true;
Preferences::AddFloatVarCache(&sMinIdlePeriod, "idle_queue.min_period",
DEFAULT_MIN_IDLE_PERIOD);
}
return sMinIdlePeriod;
}
/* static */ uint32_t
MainThreadIdlePeriod::GetMaxTimerThreadBound()
{
MOZ_ASSERT(NS_IsMainThread());
static uint32_t sMaxTimerThreadBound = DEFAULT_MAX_TIMER_THREAD_BOUND;
static bool sInitialized = false;
if (!sInitialized && Preferences::IsServiceAvailable()) {
sInitialized = true;
Preferences::AddUintVarCache(&sMaxTimerThreadBound, "idle_queue.max_timer_thread_bound",
DEFAULT_MAX_TIMER_THREAD_BOUND);
}
return std::max(sMaxTimerThreadBound, kMaxTimerThreadBoundClamp);
}
} // namespace mozilla