Messages in this thread | | | Date | Thu, 18 Dec 2008 21:19:38 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH v7 0/8] Tunable sched_mc_power_savings=n |
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* 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
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