src/mem/dramsim2_wrapper.cc

/*
 * Copyright (c) 2013 ARM Limited
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 *
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 * property including but not limited to intellectual property relating
 * to a hardware implementation of the functionality of the software
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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
 * 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
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#include <cassert>

#include "mem/dramsim2_wrapper.hh"

#include <fstream>

#include "DRAMSim2/MultiChannelMemorySystem.h"
#include "base/compiler.hh"
#include "base/logging.hh"

/**
 * DRAMSim2 requires SHOW_SIM_OUTPUT to be defined (declared extern in
 * the DRAMSim2 print macros), otherwise we get linking errors due to
 * undefined references
 */
int SHOW_SIM_OUTPUT = 0;

namespace gem5
{

namespace memory
{

DRAMSim2Wrapper::DRAMSim2Wrapper(const std::string& config_file,
                                 const std::string& system_file,
                                 const std::string& working_dir,
                                 const std::string& trace_file,
                                 unsigned int memory_size_mb,
                                 bool enable_debug) :
    dramsim(new DRAMSim::MultiChannelMemorySystem(config_file, system_file,
                                                  working_dir, trace_file,
                                                  memory_size_mb, NULL, NULL)),
    _clockPeriod(0.0), _queueSize(0), _burstSize(0)
{
    // tell DRAMSim2 to ignore its internal notion of a CPU frequency
    dramsim->setCPUClockSpeed(0);

    // switch on debug output if requested
    if (enable_debug)
        SHOW_SIM_OUTPUT = 1;

    // there is no way of getting DRAMSim2 to tell us what frequency
    // it is assuming, so we have to extract it ourselves
    _clockPeriod = extractConfig<double>("tCK=",
                                         working_dir + '/' + config_file);

    if (!_clockPeriod)
        fatal("DRAMSim2 wrapper failed to get clock\n");

    // we also need to know what transaction queue size DRAMSim2 is
    // using so we can stall when responses are blocked
   _queueSize = extractConfig<unsigned int>("TRANS_QUEUE_DEPTH=",
                                            working_dir + '/' + system_file);

    if (!_queueSize)
        fatal("DRAMSim2 wrapper failed to get queue size\n");


   // finally, get the data bus bits and burst length so we can add a
   // sanity check for the burst size
    unsigned int dataBusBits =
        extractConfig<unsigned int>("JEDEC_DATA_BUS_BITS=",
                                    working_dir + '/' + system_file);
   unsigned int burstLength =
       extractConfig<unsigned int>("BL=", working_dir + '/' + config_file);

   if (!dataBusBits || !burstLength)
       fatal("DRAMSim22 wrapper failed to get burst size\n");

   _burstSize = dataBusBits * burstLength / 8;
}

DRAMSim2Wrapper::~DRAMSim2Wrapper()
{
    delete dramsim;
}

template <typename T>
T
DRAMSim2Wrapper::extractConfig(const std::string& field_name,
                               const std::string& file_name) const
{
    std::ifstream file_stream(file_name.c_str(), ios::in);

    if (!file_stream.good())
        fatal("DRAMSim2 wrapper could not open %s for reading\n", file_name);

    bool found = false;
    T res;
    std::string line;
    while (!found && file_stream) {
        getline(file_stream, line);
        if (line.substr(0, field_name.size()) == field_name) {
            found = true;
            istringstream iss(line.substr(field_name.size()));
            iss >> res;
        }
    }

    file_stream.close();

    if (!found)
        fatal("DRAMSim2 wrapper could not find %s in %s\n", field_name,
              file_name);

    return res;
}

void
DRAMSim2Wrapper::printStats()
{
    dramsim->printStats(true);
}

void
DRAMSim2Wrapper::setCallbacks(DRAMSim::TransactionCompleteCB* read_callback,
                              DRAMSim::TransactionCompleteCB* write_callback)
{
    // simply pass it on, for now we ignore the power callback
    dramsim->RegisterCallbacks(read_callback, write_callback, NULL);
}

bool
DRAMSim2Wrapper::canAccept() const
{
    return dramsim->willAcceptTransaction();
}

void
DRAMSim2Wrapper::enqueue(bool is_write, uint64_t addr)
{
    [[maybe_unused]] bool success = dramsim->addTransaction(is_write, addr);
    assert(success);
}

double
DRAMSim2Wrapper::clockPeriod() const
{
    return _clockPeriod;
}

unsigned int
DRAMSim2Wrapper::queueSize() const
{
    return _queueSize;
}

unsigned int
DRAMSim2Wrapper::burstSize() const
{
    return _burstSize;
}

void
DRAMSim2Wrapper::tick()
{
    dramsim->update();
}

} // namespace memory
} // namespace gem5