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
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 * modified or unmodified, in source code or in binary form.
 *
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 * met: redistributions of source code must retain the above copyright
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 * redistributions in binary form must reproduce the above copyright
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#ifndef __CPU_KVM_TIMER_HH__
#define __CPU_KVM_TIMER_HH__
 
#include <ctime>
 
#include "cpu/kvm/perfevent.hh"
#include "sim/core.hh"
 
namespace gem5
{
 
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;
    virtual bool expired() {
        return true;
    }
 
    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 * sim_clock::as_float::ns;
    }
 
  protected:
    virtual Tick calcResolution() = 0;
 
    uint64_t hostNs(Tick ticks) {
        return ticks / (sim_clock::as_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) override;
    void disarm() override;
    bool expired() override;
 
  protected:
    Tick calcResolution() override;
 
  private:
    clockid_t clockID;
    timer_t timer;
    struct itimerspec prevTimerSpec;
};
 
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;
};
 
} // namespace gem5
 
#endif