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authorStephan Diestelhorst <stephan.diestelhorst@arm.com>2014-08-12 19:00:44 +0100
committerStephan Diestelhorst <stephan.diestelhorst@arm.com>2014-08-12 19:00:44 +0100
commit16351ba8d6b98e4dc0012cfc4083fe93ec6d76ce (patch)
tree59c73b35dd747121f962e03f7d43a45a824ced9a
parent65aaf62714f783073b994f89fddf8558332607e8 (diff)
downloadgem5-16351ba8d6b98e4dc0012cfc4083fe93ec6d76ce.tar.xz
energy: Tighter checking of levels for DFS systems
There are cases where users might by accident / intention specify less voltage operating points thatn frequency points. We consider one of these cases special: giving only a single voltage to a voltage domain effectively renders it as a static domain. This patch adds additional logic in the auxiliary parts of the functionality to handle these cases properly (simple driver asking for N>1 operating levels, we should return the same voltage for all of them) and adds error checking code in the voltage domain.
-rw-r--r--src/sim/dvfs_handler.hh30
-rw-r--r--src/sim/voltage_domain.hh4
2 files changed, 32 insertions, 2 deletions
diff --git a/src/sim/dvfs_handler.hh b/src/sim/dvfs_handler.hh
index 3ff08115a..a8b78d08b 100644
--- a/src/sim/dvfs_handler.hh
+++ b/src/sim/dvfs_handler.hh
@@ -137,7 +137,15 @@ class DVFSHandler : public SimObject
*/
Tick clkPeriodAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
{
- return findDomain(domain_id)->clkPeriodAtPerfLevel(perf_level);
+ SrcClockDomain *d = findDomain(domain_id);
+ assert(d);
+ PerfLevel n = d->numPerfLevels();
+ if (perf_level < n)
+ return d->clkPeriodAtPerfLevel(perf_level);
+
+ warn("DVFSHandler %s reads illegal frequency level %u from "\
+ "SrcClockDomain %s. Returning 0\n", name(), perf_level, d->name());
+ return Tick(0);
}
/**
@@ -150,7 +158,25 @@ class DVFSHandler : public SimObject
*/
double voltageAtPerfLevel(DomainID domain_id, PerfLevel perf_level) const
{
- return findDomain(domain_id)->voltageDomain()->voltage(perf_level);
+ VoltageDomain *d = findDomain(domain_id)->voltageDomain();
+ assert(d);
+ PerfLevel n = d->numVoltages();
+ if (perf_level < n)
+ return d->voltage(perf_level);
+
+ // Request outside of the range of the voltage domain
+ if (n == 1) {
+ DPRINTF(DVFS, "DVFS: Request for perf-level %i for single-point "\
+ "voltage domain %s. Returning voltage at level 0: %.2f "\
+ "V\n", perf_level, d->name(), d->voltage(0));
+ // Special case for single point voltage domain -> same voltage for
+ // all points
+ return d->voltage(0);
+ }
+
+ warn("DVFSHandler %s reads illegal voltage level %u from "\
+ "VoltageDomain %s. Returning 0 V\n", name(), perf_level, d->name());
+ return 0.;
}
/**
diff --git a/src/sim/voltage_domain.hh b/src/sim/voltage_domain.hh
index 9ffbe7bbc..ab96abad8 100644
--- a/src/sim/voltage_domain.hh
+++ b/src/sim/voltage_domain.hh
@@ -77,6 +77,10 @@ class VoltageDomain : public SimObject
*/
double voltage(PerfLevel perf_level) const
{
+ chatty_assert(perf_level < numVoltages(), "VoltageDomain %s "\
+ "request for voltage perf level %u is outside "\
+ "of numVoltages %u", name(), perf_level,
+ numVoltages());
return voltageOpPoints[perf_level];
}