src/sim/power/mathexpr_powermodel.cc

/*
 * Copyright (c) 2016-2017 ARM Limited
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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
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 * documentation and/or other materials provided with the distribution;
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 * 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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 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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 * Authors: David Guillen Fandos
 */

#include "sim/power/mathexpr_powermodel.hh"

#include <string>

#include "base/statistics.hh"
#include "params/MathExprPowerModel.hh"
#include "sim/mathexpr.hh"
#include "sim/power/thermal_model.hh"
#include "sim/sim_object.hh"

MathExprPowerModel::MathExprPowerModel(const Params *p)
    : PowerModelState(p), dyn_expr(p->dyn), st_expr(p->st), failed(false)
{
    // Calculate the name of the object we belong to
    std::vector<std::string> path;
    tokenize(path, name(), '.', true);
    // It's something like xyz.power_model.pm2
    assert(path.size() > 2);
    for (unsigned i = 0; i < path.size() - 2; i++)
        basename += path[i] + ".";
}

void
MathExprPowerModel::startup()
{
    // Create a map with stats and pointers for quick access
    // Has to be done here, since we need access to the statsList
    for (auto & i: Stats::statsList()) {
        if (i->name.find(basename) == 0) {
            // Add stats for this sim object and its child objects
            stats_map[i->name.substr(basename.size())] = i;
        } else if (i->name.find(".") == std::string::npos) {
            // Add global stats (sim_seconds, for example)
            stats_map[i->name] = i;
        }
    }

    tryEval(st_expr);
    const bool st_failed = failed;

    tryEval(dyn_expr);
    const bool dyn_failed = failed;

    if (st_failed || dyn_failed) {
        const auto *p = dynamic_cast<const Params *>(params());
        assert(p);

        fatal("Failed to evaluate power expressions:\n%s%s%s\n",
              st_failed ? p->st : "",
              st_failed && dyn_failed ? "\n" : "",
              dyn_failed ? p->dyn : "");
    }
}

double
MathExprPowerModel::eval(const MathExpr &expr) const
{
    const double value = tryEval(expr);

    // This shouldn't happen unless something went wrong the equations
    // were verified in startup().
    panic_if(failed, "Failed to evaluate power expression '%s'\n",
             expr.toStr());

    return value;
}

double
MathExprPowerModel::tryEval(const MathExpr &expr) const
{
    failed = false;
    const double value = expr.eval(
        std::bind(&MathExprPowerModel::getStatValue,
                  this, std::placeholders::_1)
        );

    return value;
}


double
MathExprPowerModel::getStatValue(const std::string &name) const
{
    using namespace Stats;

    // Automatic variables:
    if (name == "temp") {
        return _temp;
    } else if (name == "voltage") {
        return clocked_object->voltage();
    }

    // Try to cast the stat, only these are supported right now
    const auto it = stats_map.find(name);
    if (it == stats_map.cend()) {
        warn("Failed to find stat '%s'\n", name);
        failed = true;
        return 0;
    }

    const Info *info = it->second;

    auto si = dynamic_cast<const ScalarInfo *>(info);
    if (si)
        return si->value();
    auto fi = dynamic_cast<const FormulaInfo *>(info);
    if (fi)
        return fi->total();

    panic("Unknown stat type!\n");
}

void
MathExprPowerModel::regStats()
{
    PowerModelState::regStats();
}

MathExprPowerModel*
MathExprPowerModelParams::create()
{
    return new MathExprPowerModel(this);
}