js/ipc/CPOWTimer.cpp
author David Rajchenbach-Teller <dteller@mozilla.com>
Mon, 17 Aug 2015 14:57:23 +0200
changeset 258423 38ac1237696c6a5ac64184403795a0b6c63f9a56
parent 257130 9e01460eca0cb4b6ffb53a1ba692c27322020d8a
child 303949 0fdce8a8b9201278343d4697725850d2b33374c8
permissions -rw-r--r--
Bug 1181175 - Use RDTSC for Performance Monitoring instead of getrusage. r=jandem

/* -*- Mode: C++; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*-
 * vim: set ts=4 sw=4 et 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 "jsfriendapi.h"
#include "nsContentUtils.h"
#include "CPOWTimer.h"

#include "jsapi.h"

CPOWTimer::CPOWTimer(JSContext* cx MOZ_GUARD_OBJECT_NOTIFIER_PARAM_IN_IMPL)
    : cx_(nullptr)
    , startInterval_(0)
{
    MOZ_GUARD_OBJECT_NOTIFIER_INIT;
    JSRuntime* runtime = JS_GetRuntime(cx);
    if (!js::GetStopwatchIsMonitoringCPOW(runtime))
        return;
    cx_ = cx;
    startInterval_ = JS_Now();
}
CPOWTimer::~CPOWTimer()
{
    if (!cx_) {
        // Monitoring was off when we started the timer.
        return;
    }

    JSRuntime* runtime = JS_GetRuntime(cx_);
    if (!js::GetStopwatchIsMonitoringCPOW(runtime)) {
        // Monitoring has been deactivated while we were in the timer.
        return;
    }

    const int64_t endInterval = JS_Now();
    if (endInterval <= startInterval_) {
        // Do not assume monotonicity.
        return;
    }

    js::AddCPOWPerformanceDelta(runtime, endInterval - startInterval_);
}