Re: volano ~30% regression with 2.6.33-rc1 & -rc2

From: Mike Galbraith
Date: Mon Jan 04 2010 - 07:57:47 EST


On Mon, 2010-01-04 at 04:40 -0800, Arjan van de Ven wrote:
> On Mon, 04 Jan 2010 16:15:58 +0800
> Lin Ming <ming.m.lin@xxxxxxxxx> wrote:
>
> > Mike & Peter,
> >
> > Compared with 2.6.32, volano has ~30% regression with 2.6.33-rc1 &
> > -rc2. Testing machine: Tigerton Xeon, 16cpus(4P/4Core), 16G memory
>
> did this show up only on this cpu?
> (since this is a multi-core-without-shared-cache cpu, it could be that
> we get the topology wrong and think cores share cache where they don't)

My fault for using PREFER_SIBLING I guess. However, I do wonder why in
the heck we set that at the CPU domain level. Siblings lie northward.

-Mike

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/