Messages in this thread |  | | | Date | Wed, 9 Jan 2008 14:20:14 +0100 | | From | Ingo Molnar <> | | Subject | Re: Analysis of sched_mc_power_savings |
* Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote:
> I will watch this during the experiments. I have been using klog
> application to dump relayfs data. I did run powertop and top as well,
> I will bind them to certain CPUs and isolate their impact.
> > I believe the margin of error would be less since all the measurement
> tasks sleep for long duration.
ok, long duration ought to be enough.
i think a possible explanation of your observtions would be this: sleepy
workloads are affected more by the wakeup logic, and most of the
power-savings works via runtime balancing.
So perhaps try to add some SD_POWERSAVINGS_BALANCE logic to
try_to_wake_up()? I think waking up on the same CPU where it went to
sleep is the most power-efficient approach in general. (or always waking
up where the wakee runs - this should be measured.) Right now
try_to_wake_up() tries to spread out load opportunistically, which is
throughput-maximizing but it's arguably not very power conscious.
Ingo
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