Messages in this thread |  | | | Date | Fri, 19 Dec 2008 13:54:31 +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> [2008-12-18 21:19:38]:
> > * Vaidyanathan Srinivasan <svaidy@linux.vnet.ibm.com> wrote: > > > Hi, > > > > The existing power saving loadbalancer CONFIG_SCHED_MC attempts to run > > the workload in the system on minimum number of CPU packages and tries > > to keep rest of the CPU packages idle for longer duration. Thus > > consolidating workloads to fewer packages help other packages to be in > > idle state and save power. The current implementation is very > > conservative and does not work effectively across different workloads. > > Initial idea of tunable sched_mc_power_savings=n was proposed to enable > > tuning of the power saving load balancer based on the system > > configuration, workload characteristics and end user requirements. > > > > The power savings and performance of the given workload in an under > > utilised system can be controlled by setting values of 0, 1 or 2 to > > /sys/devices/system/cpu/sched_mc_power_savings with 0 being highest > > performance and least power savings and level 2 indicating maximum power > > savings even at the cost of slight performance degradation. > > > > Please refer to the following discussions and article for details. > > > > [1]Making power policy just work > > http://lwn.net/Articles/287924/ > > > > [2][RFC v1] Tunable sched_mc_power_savings=n > > http://lwn.net/Articles/287882/ > > > > v2: http://lwn.net/Articles/297306/ > > v3: http://lkml.org/lkml/2008/11/10/260 > > v4: http://lkml.org/lkml/2008/11/21/47 > > v5: http://lkml.org/lkml/2008/12/11/178 > > v6: http://lwn.net/Articles/311830/ > > > > The following series of patch demonstrates the basic framework for > > tunable sched_mc_power_savings. > > > > This version of the patch incorporates comments and feedback received > > on the previous post from Andrew Morton. > > > > Changes form v6: > > ---------------- > > * Convert BALANCE_FOR_xx_POWER and related macros to inline functions > > based on comments from Andrew and Ingo. > > * Ran basic kernelbench test and did not see any performance variation > > due to the changes. > > > > Changes form v5: > > --------------- > > * Fixed the sscanf bug and checking for (p->flags & PF_KTHREAD) > > * Dropped the RFC prefix to indicate that the patch is ready for > > testing and inclusion > > * Patch series against 2.6.28-rc8 kernel > > thanks, applied - and i started testing them. It needed some help here and > there to resolve conflicts with pending cpumask changes. Could you please > double-check the merged up end result in the latest scheduler devel tree: > > http://people.redhat.com/mingo/tip.git/README
Thanks Ingo. I will review and check the cpumask changes. I will test the tip tree as well and provide you feedback.
I will look forward to test/bug reports from others on the patch series and help with the fix.
--Vaidy
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