Re: volanoMark regression with kernel 2.6.26-rc1

Mike Galbraith
2008-05-14T14:50:49Z

On Wed, 2008-05-14 at 19:14 +0530, Srivatsa Vaddagiri wrote:
> On Mon, May 12, 2008 at 11:20:47AM +0200, Peter Zijlstra wrote:
> > It looks like things like find_busiest_group() just think everything is
> > peachy when the imbalance is < 1 task - which with all this grouping
> > stuff is not necessarily true.
>
> fwiw, the following hack seems to help bring down regression to ~5%
> (b/n 2.6.25 and 2.6.26-rc1 with USER_SCHED):
>
> Also in the patch GROUP_SCALE can probably be less than what I used (and
> needs a ifdef GROUP_SCHED) ..

On my little Q6600 with git.today, it made no real difference, whether
NORMALIZED_SLEEPERS was enabled or not. I see roughly 10-15% idle time
w/wo this patch, whereas pre-regression, it's < 2%.

-Mike