lkml.org 
[lkml]   [2013]   [Feb]   [21]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC PATCH v3 0/3] sched: simplify the select_task_rq_fair()
On 02/20/2013 10:05 PM, Mike Galbraith wrote:
> On Wed, 2013-02-20 at 14:32 +0100, Peter Zijlstra wrote:
>> On Wed, 2013-02-20 at 11:49 +0100, Ingo Molnar wrote:
>>
>>> The changes look clean and reasoable,
>>
>> I don't necessarily agree, note that O(n^2) storage requirement that
>> Michael failed to highlight ;-)
>
> (yeah, I mentioned that needs to shrink.. a lot)

Exactly, and I'm going to apply the suggestion now :)

>
>>> any ideas exactly *why* it speeds up?
>>
>> That is indeed the most interesting part.. There's two parts to
>> select_task_rq_fair(), the 'regular' affine wakeup path, and the
>> fork/exec find_idlest_goo() path. At the very least we need to quantify
>> which of these two parts contributes most to the speedup.
>>
>> In the power balancing discussion we already noted that the
>> find_idlest_goo() is in need of attention.
>
> Yup, even little stuff like break off the search when load is zero..

Agree, searching in a bunch of idle cpus and their subsets doesn't make
sense...

Regards,
Michael Wang

> unless someone is planning on implementing anti-idle 'course ;-)
>
> -Mike
>
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
> the body of a message to majordomo@vger.kernel.org
> More majordomo info at http://vger.kernel.org/majordomo-info.html
> Please read the FAQ at http://www.tux.org/lkml/
>



\
 
 \ /
  Last update: 2013-02-21 07:01    [W:0.111 / U:0.604 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site