lkml.org 
[lkml]   [2005]   [May]   [13]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [RFC] (How to) Let idle CPUs sleep
On Fri, May 13, 2005 at 08:29:17AM +0000, Nick Piggin wrote:
> And don't forget that the watchdog approach can just as easily deep
> sleep a CPU only to immediately wake it up again if it detects an
> imbalance.

I think we should increase the threshold beyond which the idle CPU
is woken up (more than the imbalance_pct that exists already). This
should justify waking up the CPU.

> And the CPU usage / wakeup cost arguments cut both ways. The busy
> CPUs have to do extra work in the watchdog case.

Maybe with a really smart watchdog solution, we can cut down this overhead.
I did think of other schemes - a dedicated CPU per node acting as watchdog
for that node and per-node wacthdog kernel threads? - to name a few. What I had
proposed was the best I thought. But maybe we can look at improving it
to see if the overhead concern you have can be reduced - meeting the interests
of both the worlds :)


--


Thanks and Regards,
Srivatsa Vaddagiri,
Linux Technology Center,
IBM Software Labs,
Bangalore, INDIA - 560017
-
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: 2005-05-13 11:22    [W:0.091 / U:6.184 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site