timer.hh

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/*
 * Copyright (c) 2012 ARM Limited
 * All rights reserved
 *
 * The license below extends only to copyright in the software and shall
 * not be construed as granting a license to any other intellectual
 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
 * licensed hereunder.  You may use the software subject to the license
 * terms below provided that you ensure that this notice is replicated
 * unmodified and in its entirety in all distributions of the software,
 * modified or unmodified, in source code or in binary form.
 *
 * 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
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 * neither the name of the copyright holders nor the names of its
 * contributors may be used to endorse or promote products derived from
 * this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * Authors: Andreas Sandberg
 */

#ifndef __CPU_KVM_TIMER_HH__
#define __CPU_KVM_TIMER_HH__

#include <ctime>

#include "cpu/kvm/perfevent.hh"
#include "sim/core.hh"

class BaseKvmTimer
{
  public:
    BaseKvmTimer(int signo, float hostFactor, Tick hostFreq)
        : signo(signo), _resolution(0),
          hostFactor(hostFactor), hostFreq(hostFreq) {};
    virtual ~BaseKvmTimer() {};

    virtual void arm(Tick ticks) = 0;
    virtual void disarm() = 0;

    Tick resolution() {
        if (_resolution == 0)
            _resolution = calcResolution();
        return _resolution;
    }

    Tick ticksFromHostCycles(uint64_t cycles) {
        return cycles * hostFactor * hostFreq;
    }

    Tick ticksFromHostNs(uint64_t ns) {
        return ns * hostFactor * SimClock::Float::ns;
    }

  protected:
    virtual Tick calcResolution() = 0;

    uint64_t hostNs(Tick ticks) {
        return ticks / (SimClock::Float::ns * hostFactor);
    }

    uint64_t hostCycles(Tick ticks) {
        return ticks / (hostFreq * hostFactor);
    }

    int signo;

  private:
    mutable Tick _resolution;

    float hostFactor;
    Tick hostFreq;
};

class PosixKvmTimer : public BaseKvmTimer
{
  public:
    PosixKvmTimer(int signo, clockid_t clockID,
                  float hostFactor, Tick hostFreq);
    ~PosixKvmTimer();

    void arm(Tick ticks);
    void disarm();

  protected:
    Tick calcResolution();

  private:
    clockid_t clockID;
    timer_t timer;
};

class PerfKvmTimer : public BaseKvmTimer
{
  public:
    PerfKvmTimer(PerfKvmCounter &ctr,
                 int signo,
                 float hostFactor, Tick hostFreq);
    ~PerfKvmTimer();

    void arm(Tick ticks);
    void disarm();

  protected:
    Tick calcResolution();

  private:
    PerfKvmCounter &hwOverflow;
};

#endif