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/*
* Copyright (C) 2016 Apple Inc. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
*
* THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
* PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR
* CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
* EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
* PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
* PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
* OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/
#include "config.h"
#include "SuperSampler.h"
#include "Options.h"
#include <wtf/DataLog.h>
#include <wtf/Lock.h>
#include <wtf/Seconds.h>
#include <wtf/Threading.h>
namespace JSC {
std::atomic<uint32_t> g_superSamplerCount;
std::atomic<bool> g_superSamplerEnabled;
static Lock lock;
static double in WTF_GUARDED_BY_LOCK(lock);
static double out WTF_GUARDED_BY_LOCK(lock);
void initializeSuperSampler()
{
if (!Options::useSuperSampler())
return;
Thread::create(
"JSC Super Sampler"_s,
[] () {
const int sleepQuantum = 3;
const int printingPeriod = 3000;
for (;;) {
for (int ms = 0; ms < printingPeriod; ms += sleepQuantum) {
if (g_superSamplerEnabled) {
Locker locker { lock };
if (g_superSamplerCount)
in++;
else
out++;
}
if (sleepQuantum)
sleep(Seconds::fromMilliseconds(sleepQuantum));
}
printSuperSamplerState();
if (static_cast<int32_t>(g_superSamplerCount) < 0)
dataLog("WARNING: Super sampler undercount detected!\n");
}
});
}
void resetSuperSamplerState()
{
Locker locker { lock };
in = 0;
out = 0;
}
void printSuperSamplerState()
{
if (!Options::useSuperSampler())
return;
Locker locker { lock };
double percentage = 100.0 * in / (in + out);
if (percentage != percentage)
percentage = 0.0;
dataLog("Percent time behind super sampler flag: ", percentage, "%\n");
}
void enableSuperSampler()
{
Locker locker { lock };
g_superSamplerEnabled = true;
}
void disableSuperSampler()
{
Locker locker { lock };
g_superSamplerEnabled = false;
}
} // namespace JSC
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