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sim-power: Fix the way the power model accesses stats

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With the introduction of StatGroups the organization of stats has
changed and the power modeling framework has been broken. This CL uses
the new function Stats::resolve to retrieve pointers to the necesary
stats and use them in the power estimation formulas.

Change-Id: Iedaa97eeddf51f7a0a1f222918715da309943be3
Signed-off-by: Nikos Nikoleris <nikos.nikoleris@arm.com>
Reviewed-on: https://gem5-review.googlesource.com/c/public/gem5/+/27892
Maintainer: Jason Lowe-Power <power.jg@gmail.com>
Tested-by: kokoro <noreply+kokoro@google.com>
Reviewed-by: Jason Lowe-Power <power.jg@gmail.com>
This commit is contained in:
Nikos Nikoleris
2020-03-13 12:56:54 +00:00
parent 1afe851d15
commit 274c0e0ae1
2 changed files with 23 additions and 81 deletions
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79
src/sim/power/mathexpr_powermodel.cc
View File

@@ -1,5 +1,5 @@
/*
* Copyright (c) 2016-2017 ARM Limited
* Copyright (c) 2016-2017, 2020 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@@ -46,75 +46,39 @@
#include "sim/sim_object.hh"
MathExprPowerModel::MathExprPowerModel(const Params *p)
: PowerModelState(p), dyn_expr(p->dyn), st_expr(p->st), failed(false)
: PowerModelState(p), dyn_expr(p->dyn), st_expr(p->st)
{
// 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;
for (auto expr: {dyn_expr, st_expr}) {
std::vector<std::string> vars = expr.getVariables();
for (auto var: vars) {
// Automatic variables:
if (var == "temp" || var == "voltage" || var == "clock_period") {
continue;
}
auto *info = Stats::resolve(var);
fatal_if(!info, "Failed to evaluate %s in expression:\n%s\n",
var, expr.toStr());
statsMap[var] = info;
}
}
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(
return expr.eval(
std::bind(&MathExprPowerModel::getStatValue,
this, std::placeholders::_1)
);
return value;
}
double
MathExprPowerModel::getStatValue(const std::string &name) const
{
@@ -127,18 +91,13 @@ MathExprPowerModel::getStatValue(const std::string &name) const
return clocked_object->voltage();
} else if (name=="clock_period") {
return clocked_object->clockPeriod();
}
// 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 auto it = statsMap.find(name);
assert(it != statsMap.cend());
const Info *info = it->second;
// Try to cast the stat, only these are supported right now
auto si = dynamic_cast<const ScalarInfo *>(info);
if (si)
return si->value();

25
src/sim/power/mathexpr_powermodel.hh
View File

@@ -1,5 +1,5 @@
/*
* Copyright (c) 2016-2017 ARM Limited
* Copyright (c) 2016-2017, 2020 ARM Limited
* All rights reserved
*
* The license below extends only to copyright in the software and shall
@@ -82,9 +82,8 @@ class MathExprPowerModel : public PowerModelState
*/
double getStatValue(const std::string & name) const;
void startup();
void regStats();
void startup() override;
void regStats() override;
private:
/**
@@ -96,27 +95,11 @@ class MathExprPowerModel : public PowerModelState
*/
double eval(const MathExpr &expr) const;
/**
* Evaluate an expression in the context of this object, set
* failed if evaluation failed.
*
* @param expr Expression to evaluate
* @return Value of expression.
*/
double tryEval(const MathExpr &expr) const;
// Math expressions for dynamic and static power
MathExpr dyn_expr, st_expr;
// Basename of the object in the gem5 stats hierachy
std::string basename;
// Map that contains relevant stats for this power model
std::unordered_map<std::string, Stats::Info*> stats_map;
// Did the expression fail to evaluate (e.g., because a stat value
// can't be resolved)
mutable bool failed;
std::unordered_map<std::string, const Stats::Info*> statsMap;
};
#endif