Messages in this thread | | | Date | Tue, 30 Dec 2008 23:37:22 +0530 | From | Vaidyanathan Srinivasan <> | Subject | Re: [PATCH v7 0/8] Tunable sched_mc_power_savings=n |
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* Ingo Molnar <mingo@elte.hu> [2008-12-30 07:21:39]:
> > * Balbir Singh <balbir@linux.vnet.ibm.com> wrote: > > > > > KERNBENCH Runs: make -j4 on a x86 8 core, dual socket quad core cpu > > > > package system > > > > > > > > SchedMC Run Time Package Idle Energy Power > > > > 0 81.68 52.83% 54.71% 1.00x J 1.00y W > > > > 1 80.70 36.62% 70.11% 0.95x J 0.96y W > > > > 2 74.95 19.53% 85.92% 0.90x J 0.98y W > > > > Your result is very interesting. > > > level 2 is more fast and efficient of power. > > > > > > What's major contributor to use less time in level 2? > > > I think it's cache bounce is less time than old. > > > Is right ? > > > > Yes, correct > > yes, i too noticed that runtime improved so dramatically: +7.5% on > kernbench is a _very_ big deal. > > So i wanted to ask you to re-test whether this speedup is reproducible, > and if yes, please check a few other workloads (for example sysbench on > postgresql / mysqld) and send a patch that changes the > sched_mc_power_savings default to POWERSAVINGS_BALANCE_WAKEUP (2).
The speedup for kernbench is reproducible. I will post a more detailed test report on kernbench soon. The power-performance benefit is for an under-utilised system (nr_cpus/2) run of kernbench which is very ideal to demonstrate the power savings feature. I will also try sysbench and update results little later. As Balbir mentioned, I am on vacation and traveling. I will post more benchmark results as soon as possible.
--Vaidy
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