lkml.org 
[lkml]   [2012]   [Aug]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [discussion]sched: a rough proposal to enable power saving in scheduler
On 8/15/2012 6:14 PM, Rik van Riel wrote:
> On 08/15/2012 10:43 AM, Arjan van de Ven wrote:
>
>> The easy cop-out is provide the sysadmin a slider.
>> The slightly less easy one is to (and we're taking this approach
>> in the new P state code we're working on) say "in the default
>> setting, we're going to sacrifice up to 5% performance from peak
>> to give you the best power savings within that performance loss budget"
>> (with a slider that can give you 0%, 2 1/2% 5% and 10%)
>
> On a related note, I am looking at the c-state menu governor.
>
> We seem to have issues there, with Linux often going into a much
> deeper C state than warranted, which can lead to a fairly steep
> performance penalty for some workloads.
>

predicting the future is hard.
if you pick a too deep C state, you get a certain fixed performance hit
if you pick a too shallow C state, you get a pretty large power hit (depending on how long you actually stay idle)

also would need to know hw details; at least on Intel a bunch of things are done
by the firmware and some platforms we're not doing the right things as Linux
(or BIOS)



\
 
 \ /
  Last update: 2012-08-16 04:03    [W:0.142 / U:0.372 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site