Re: [PATCH] sched: Reduce contention in update_cfs_rq_blocked_load

[Peter Zijlstra <peterz@infradead.org>]

On Fri, Aug 08, 2014 at 06:30:08AM +0800, Yuyang Du wrote:
> > > > -----------------------------------------------------
> > > >               |   10-90   |  100-1000   |  1100-2000
> > > >               |   users   |   users     |   users
> > > > -----------------------------------------------------
> > > > alltests      |   -3.37%  |  -10.64%    |   -2.25%
> > > > -----------------------------------------------------
> > > > all_utime     |   +0.33%  |   +3.73%    |   +3.33%
> > > > -----------------------------------------------------
> > > > compute       |   -5.97%  |   +2.34%    |   +3.22%
> > > > -----------------------------------------------------
> > > > custom        |  -31.61%  |  -10.29%    |  +15.23%
> > > > -----------------------------------------------------
> > > > disk          |  +24.64%  |  +28.96%    |  +21.28%
> > > > -----------------------------------------------------
> > > > fserver       |   -1.35%  |   +4.82%    |   +9.35%
> > > > -----------------------------------------------------
> > > > high_systime  |   -6.73%  |   -6.28%    |  +12.36%
> > > > -----------------------------------------------------
> > > > shared        |  -28.31%  |  -19.99%    |   -7.10%
> > > > -----------------------------------------------------
> > > > short         |  -44.63%  |  -37.48%    |  -33.62%
> > > > -----------------------------------------------------

> Thanks a lot, Jason.
> 
> So for this particular set of workloads on a big machine, I think the
> result is mixed and overall "neutral", but I expected the variation probably
> could be bigger especially for light workloads.
> 
> Any comment from the maintainers and others? Ping Peter and Ben, I haven't
> heard from you for the 5th version.

Been a bit busy.. but in general I worry about the performance decrease
on the lighter loads. I should probably run some workloads on my 2
socket and 4 socket machines, but the coming few weeks will be very busy
and I'm afraid I'll not get around to it in a timely manner.