lkml.org 
[lkml]   [2006]   [Feb]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [rfc][patch] sched: remove smpnice
Peter Williams wrote:
> Andrew Morton wrote:
>
>> "Siddha, Suresh B" <suresh.b.siddha@intel.com> wrote:
>>
>>> b) On a lightly loaded system, this can result in HT scheduler
>>> optimizations
>>> being disabled in presence of low priority tasks... in this case,
>>> they(low
>>> priority ones) can end up running on the same package, even in the
>>> presence of other idle packages.. Though this is not as serious as
>>> "a" above...
>>>
>
> I think that this issue comes under the heading of "Result of better
> nice enforcement" which is the purpose of the patch :-).

On the assumption that this enforcement is considered to be too
vigorous, I think that it is also amenable to a fix based on a new
biased_load() function by replacing the (*imbalance < SCHED_LOAD_SCALE)
test with (biased_load(*imbalance, busiest) == 0) and (possibly) some
modifications within the if statement's body (most notably replacing the
NICE_TO_BIAS_PRIO(0) expressions with (busiest->prio_bias /
busiest->nr_running) or something similar).

This change would cause no change in functionality in the case where all
tasks are nice==0.

Peter
--
Peter Williams pwil3058@bigpond.net.au

"Learning, n. The kind of ignorance distinguishing the studious."
-- Ambrose Bierce
-
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: 2006-02-11 05:08    [W:0.117 / U:0.512 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site