lkml.org 
[lkml]   [2012]   [Jan]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH] x86,sched: Fix sched_smt_power_savings totally broken
On 1/10/2012 1:18 AM, Ingo Molnar wrote:
>
> * Suresh Siddha <suresh.b.siddha@intel.com> wrote:
>
>> On Tue, 2012-01-10 at 00:58 -0500, Youquan Song wrote:
>>> Thanks Peter! Here is the patch.
>>
>> Youquan, As far as I know both the
>> sched_smt_power_savings/sched_mc_power_savings are broken for atleast an
>> year.
>
> We want a single knob, sched_power_savings - with the mc_ and
> smt_ ones still kept and aliased to sched_power_savings, for
> compatibility reasons.
>
> As Peter said, the other reasonable option is to have no knob at
> all and restart this code from scratch.
>
> The other thing we should do is to add sane defaults: to turn on
> sched_power_savings *AUTOMATICALLY* when a system is obviously
> battery driven and turn it off when the system is obviously AC
> driven. User-space can still implement policy and override the
> kernel's default, but there's absolutely no excuse to not offer
> this default ourselves.

a very good default would be to keep all tasks on one package until half
the cores in the package are busy, and then start spreading out.

I suspect that'll be the 90% case coverage.


\
 
 \ /
  Last update: 2012-01-10 15:35    [from the cache]
©2003-2011 Jasper Spaans