Re: [RFC] The Linux Scheduler: a Decade of Wasted Cores Report

Mike Galbraith
2016-04-25T09:18:50Z

On Sun, 2016-04-24 at 09:05 +0200, Mike Galbraith wrote:
> On Sat, 2016-04-23 at 18:38 -0700, Brendan Gregg wrote:
>
> > The bugs they found seem real, and their analysis is great (although
> > using visualizations to find and fix scheduler bugs isn't new), and it
> > would be good to see these fixed. However, it would also be useful to
> > double check how widespread these issues really are. I suspect many on
> > this list can test these patches in different environments.
>
> Part of it sounded to me very much like they're meeting and "fixing"
> SMP group fairness...

Ew, NUMA boxen look like they could use a hug or two. Add a group of
one hog to compete with a box wide kbuild, ~lose a node.

Master.today, 4 node box, make -j 192 modules

root group
real 1m6.987s 1.00

cgroup vs 1 group of 1 hog
real 1m20.871s 1.20

cgroup vs 2 groups of 1 hog
real 1m48.803s 1.62

-Mike