RE: [RFC PATCH 0/4]: affinity-on-next-touch

From: Stefan Lankes
Date: Mon May 11 2009 - 13:22:45 EST




> -----Original Message-----
> From: Andi Kleen [mailto:andi@xxxxxxxxxxxxxx]
> Sent: Monday, May 11, 2009 6:37 PM
> To: Stefan Lankes
> Cc: 'Andi Kleen'; linux-kernel@xxxxxxxxxxxxxxx;
> Lee.Schermerhorn@xxxxxx; linux-numa@xxxxxxxxxxxxxxx;
> brice.goglin@xxxxxxxx; 'Terboven, Christian'; anmey@xxxxxxxxxxxxxxxxx;
> 'Boris Bierbaum'
> Subject: Re: [RFC PATCH 0/4]: affinity-on-next-touch
>
> > By default, mbind only has an effect on new allocations. I think that
> this
>
> Nope, it affects existing pages too, it can even move pages
> if you ask for it.
>

I know this possibility. I thought that "affinity-on-next-touch" fit better
to madvise. Brice told already the technical reasons for preferring of
madvise.

> > For instance, Norden's PDE solvers using adaptive mesh refinements
> (AMR) [1]
> > is an application with a dynamic access pattern. We use this example
> to
> > evaluate the performance of our patch. We ran this solver on our
> > quad-socket, dual-core Opteron 875 (2.2GHz) system running CentOS
> 5.2. The
> > code was already optimized for NUMA architectures. Before the arrays
> are
> > initialized, the threads are bound to one core. In our test case, the
> solver
> > needs 5318s. If we use our kernel extension, the solver needs 4489s.
>
> Okay that sounds like good numbers.
>
> > Currently, we are testing some other apps.
>
> Please keep the list updated.
>

I will do it.

Stefan

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