Re: [RFC PATCH] sched: Pass affine target cpu into wake_affine

[Lin Ming <ming.m.lin@intel.com>]

On Thu, 2010-01-07 at 21:14 +0800, Mike Galbraith wrote:
> On Thu, 2010-01-07 at 16:45 +0800, Lin Ming wrote:
> > On Tue, 2010-01-05 at 14:43 +0800, Mike Galbraith wrote:
> > > On Tue, 2010-01-05 at 04:44 +0100, Mike Galbraith wrote:
> > > > On Tue, 2010-01-05 at 10:48 +0800, Lin Ming wrote:
> > > > > On Mon, 2010-01-04 at 17:03 +0800, Lin Ming wrote:
> > > > > > commit a03ecf08d7bbdd979d81163ea13d194fe21ad339
> > > > > > Author: Lin Ming <ming.m.lin@intel.com>
> > > > > > Date:   Mon Jan 4 14:14:50 2010 +0800
> > > > > > 
> > > > > >     sched: Pass affine target cpu into wake_affine
> > > > > >     
> > > > > >     Since commit a1f84a3(sched: Check for an idle shared cache in select_task_rq_fair()),
> > > > > >     the affine target maybe adjusted to any idle cpu in cache sharing domains
> > > > > >     instead of current cpu.
> > > > > >     But wake_affine still use current cpu to calculate load which is wrong.
> > > > > >     
> > > > > >     This patch passes affine cpu into wake_affine.
> > > > > >     
> > > > > >     Signed-off-by: Lin Ming <ming.m.lin@intel.com>
> > > > > 
> > > > > Mike,
> > > > > 
> > > > > Any comment of this patch?
> > > > 
> > > > The patch definitely looks like the right thing to do, but when I tried
> > > > this, it didn't work out well.  Since I can't seem to recall precise
> > > > details, I'll let my box either remind me or give it's ack.
> > > 
> > > Unfortunately, box reminded me.  mysql+oltp peak throughput with
> > > nr_clients == nr_cpus
> > 
> > Did you test with your vmark regression fix patch also applied?
> 
> Below is a complete retest.  Mind testing my hacklet?  I bet a nickle
> it'll work at least as well as yours on your beefy boxen.

I tested your hacklet on below 2 machines as before.

Tigerton x86_64 machine: 16cpus(4P/4Cores), 40G mem
IA64 machine: 32cpus(4P/4Cores/HT), 16G mem

Test1: vmark regression fix patch + pass affine target
Test2: this hacklet

Compared with upstream 2.6.33-rc2, 
Test1: Tigerton +3%, IA64 +15%
Test2: Tigerton +3%, IA64 +10%

The test2 also improves on IA64, although not as good as test1.

I also tested tbench, this hacklet does not help.

Lin Ming