Re: VolanoMark regression with 2.6.27-rc1

["Zhang, Yanmin" <yanmin_zhang@linux.intel.com>]

On Thu, 2008-08-21 at 08:16 +0200, Ingo Molnar wrote:
> * Zhang, Yanmin <yanmin_zhang@linux.intel.com> wrote:
> 
> > > ok, i've applied this one to tip/sched/urgent instead of the 
> > > feature-disabling patchlet. Yanmin, could you please check whether this 
> > > one does the trick?
> >
> > This new patch almost doesn't help volanoMark. Pls. use the patch 
> > which sets LB_BIAS=1 by default.
> 
> ok. That also removes the kernel.h complications ;-)
Sorry, I have new update.
Originally, I worked on 2.6.27-rc1. I just move to 2.6.27-rc3 and found
something defferent when CONFIG_GROUP_SCHED=n.

With 2.6.27-rc3, on my 8-core stoakley, all volanoMark regression disappears,
no matter if I enable LB_BIAS. On 16-core tigerton, the regression is still
there if I don't enable LB_BIAS and regression becomes 11% from 65%.

8-core stoakley:
2.6.26_nogroup			340669
2.6.27-rc1_nogroup		267237
2.6.27-rc1_nogroup+LB_BIAS=1	330693
2.6.27-rc3_nogroup		352193
2.6.27-rc3_nogroup+LB_BIAS=1	355872

16-core tigerton:
2.6.26_nogroup			539644
2.6.27-rc1_nogroup		309334
2.6.27-rc1_nogroup+LB_BIAS=1	478360
2.6.27-rc3_nogroup		348426
2.6.27-rc3_nogroup+LB_BIAS=1	483150

-yanmin