random_gen.cc

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/*
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 * Authors: Thomas Grass
 *          Andreas Hansson
 *          Sascha Bischoff
 *          Neha Agarwal
 */

#include "cpu/testers/traffic_gen/random_gen.hh"

#include <algorithm>

#include "base/random.hh"
#include "base/trace.hh"
#include "debug/TrafficGen.hh"

void
RandomGen::enter()
{
    // reset the counter to zero
    dataManipulated = 0;
}

PacketPtr
RandomGen::getNextPacket()
{
    // choose if we generate a read or a write here
    bool isRead = readPercent != 0 &&
        (readPercent == 100 || random_mt.random(0, 100) < readPercent);

    assert((readPercent == 0 && !isRead) || (readPercent == 100 && isRead) ||
           readPercent != 100);

    // address of the request
    Addr addr = random_mt.random(startAddr, endAddr - 1);

    // round down to start address of block
    addr -= addr % blocksize;

    DPRINTF(TrafficGen, "RandomGen::getNextPacket: %c to addr %x, size %d\n",
            isRead ? 'r' : 'w', addr, blocksize);

    // add the amount of data manipulated to the total
    dataManipulated += blocksize;

    // create a new request packet
    return getPacket(addr, blocksize,
                     isRead ? MemCmd::ReadReq : MemCmd::WriteReq);
}

Tick
RandomGen::nextPacketTick(bool elastic, Tick delay) const
{
    // Check to see if we have reached the data limit. If dataLimit is
    // zero we do not have a data limit and therefore we will keep
    // generating requests for the entire residency in this state.
    if (dataLimit && dataManipulated >= dataLimit)
    {
        DPRINTF(TrafficGen, "Data limit for RandomGen reached.\n");
        // No more requests. Return MaxTick.
        return MaxTick;
    } else {
        // return the time when the next request should take place
        Tick wait = random_mt.random(minPeriod, maxPeriod);

        // compensate for the delay experienced to not be elastic, by
        // default the value we generate is from the time we are
        // asked, so the elasticity happens automatically
        if (!elastic) {
            if (wait < delay)
                wait = 0;
            else
                wait -= delay;
        }

        return curTick() + wait;
    }
}