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
> I had tested sched_mc_powersavings=2 on dual socket quad core HT
> nehalem. It worked as expected. Let me check the
> sched_mc_powersavings=1 case. I will not be surprised if it is
> broken.
>

In my opinion. When CPU cores > 8, sched_mc will have issue of course.
What's more, when CPU cores increase it will be abviously if following
current CPU power capability calcaluation logic.

If CPU has 8 cores and if HT enabled, its power capability > 9 cores.
Current logic, HT enable core power capability = 1178, 1178 * 8
/ 1024 > 9.2. So scheduler will try to schedule >8 threads to meet its
power capability before use other socket if sched_mc used.

So it will be better, like this: Of course, It is only sample code
and I do not try it yet.

For MC:
+ if (sched_mc_power_savings)
+ sgs->group_capacity = group->group_weight/2;

For SMT:
+ if (sched_smt_power_savings && !(sd->flags & SD_SHARE_CPUPOWER))
+ sgs->group_capacity = group->group_weight;


Thanks
-Youquan


\
 
 \ /
  Last update: 2012-01-11 05:23    [W:0.291 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site