rdtsc.hpp

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//============================================================================
// vSMC/include/vsmc/utility/rdtsc.hpp
//----------------------------------------------------------------------------
//                         vSMC: Scalable Monte Carlo
//----------------------------------------------------------------------------
// Copyright (c) 2013,2014, Yan Zhou
// All rights reserved.
//
// Redistribution and use in source and binary forms, with or without
// modification, are permitted provided that the following conditions are met:
//
//   Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
//
//   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 THE COPYRIGHT HOLDERS AND CONTRIBUTORS 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 THE COPYRIGHT HOLDER 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
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// ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
// POSSIBILITY OF SUCH DAMAGE.
//============================================================================

#ifndef VSMC_UTILITY_RDTSC_HPP
#define VSMC_UTILITY_RDTSC_HPP

#include <vsmc/internal/common.hpp>

#ifdef VSMC_MSVC
#include <intrin.h>
#endif

namespace vsmc {

inline uint64_t rdtsc ()
{
#ifdef VSMC_MSVC
    return static_cast<uint64_t>(__rdtsc());
#else // VSMC_MSVC
    unsigned eax = 0;
    unsigned edx = 0;
    __asm__ volatile
        (
         "rdtsc\n"
         : "=a" (eax), "=d" (edx)
        );

    return (static_cast<uint64_t>(edx) << 32) + static_cast<uint64_t>(eax);
#endif // VSMC_MSVC
}

inline uint64_t rdtscp (unsigned *aux)
{
#ifdef VSMC_MSVC
    return static_cast<uint64_t>(__rdtscp(aux));
#else // VSMC_MSVC
    unsigned eax = 0;
    unsigned ecx = 0;
    unsigned edx = 0;
    __asm__ volatile
        (
         "rdtscp\n"
         : "=a" (eax), "=c" (ecx), "=d" (edx)
        );
    *aux = ecx;

    return static_cast<uint64_t>(eax) + (static_cast<uint64_t>(edx) << 32);
#endif // VSMC_MSVC
}

class RDTSCCounter
{
    public :

    RDTSCCounter () : elapsed_(0), start_(0), running_(false) {}

    bool running () const {return running_;}

    bool start ()
    {
        if (running_)
            return false;

        running_ = true;
        start_ = rdtsc();

        return true;
    }

    bool stop ()
    {
        if (!running_)
            return false;

        uint64_t stop = rdtsc();
        if (stop < start_)
            return false;

        elapsed_ += stop - start_;
        running_ = false;

        return true;
    }

    void reset ()
    {
        elapsed_ = 0;
        running_ = false;
    }

    uint64_t cycles () const {return elapsed_;}

    private :

    uint64_t elapsed_;
    uint64_t start_;
    bool running_;
}; // class RDTSCCounter

class RDTSCPCounter
{
    public :

    RDTSCPCounter () : elapsed_(0), start_(0), start_id_(0), running_(false) {}

    bool running () const {return running_;}

    bool start ()
    {
        if (running_)
            return false;

        running_ = true;
        start_ = rdtscp(&start_id_);

        return true;
    }

    bool stop ()
    {
        if (!running_)
            return false;

        unsigned stop_id = 0;
        uint64_t stop = rdtscp(&stop_id);
        if (stop_id != start_id_ || stop < start_)
            return false;

        elapsed_ += stop - start_;
        running_ = false;

        return true;
    }

    void reset ()
    {
        elapsed_ = 0;
        running_ = false;
    }

    uint64_t cycles () const {return elapsed_;}

    private :

    uint64_t elapsed_;
    uint64_t start_;
    unsigned start_id_;
    bool running_;
}; // class RDTSCPCounter

} // namespace vsmc

#endif // VSMC_UTILITY_RDTSC_HPP