Source/WTF/wtf/TimingScope.h

/*
 * Copyright (C) 2017 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. 
 */

#pragma once

#include <wtf/MonotonicTime.h>
#include <wtf/Noncopyable.h>

namespace WTF {

// TimingScope is intended for microbenchmarking sections of code.
//
// Do not leave in shipping code.
// 
// Mean scope durations are printed using WTFLogAlways every Nth call, where N is specified by logIterationInterval.

class TimingScope {
    WTF_MAKE_FAST_ALLOCATED;
    WTF_MAKE_NONCOPYABLE(TimingScope);
public:
    TimingScope(const char* name, unsigned logIterationInterval = 1)
        : m_startTime(MonotonicTime::now())
        , m_name(name)
        , m_logIterationInterval(logIterationInterval)
    {
    }

    ~TimingScope()
    {
        scopeDidEnd();
    }

private:
    WTF_EXPORT_PRIVATE void scopeDidEnd();

    MonotonicTime m_startTime;
    const char* m_name;
    unsigned m_logIterationInterval;
};

} // namespace WTF

using WTF::TimingScope;