Re: [PATCH] Reduce TLB flushing during process migration

Martin Hicks
2004-02-17T22:07:07Z

On Tue, Feb 17, 2004 at 12:50:38PM -0800, Andrew Morton wrote:
> Martin Hicks <mort@wildopensource.com> wrote:
> >
> > Another optimization patch from Jack Steiner, intended to reduce TLB
> > flushes during process migration.
>
> This patch is only applicable to CONFIG_NUMA. Wouldn't SMP systems benefit
> from the same treatment?
>
> And does this optimisation come with any benchmark results?

Here's some figures from Jack:

---

I dont have a benchmark for JUST the scheduler change, but the entire
node history + sched change is:

nwchem on a 128p showed:

Before:
siosi7.sale.56-shm1cs: Time after atomic energies summed: 140.2
siosi7.sale.120-shm1cs: Time after atomic energies summed: 306.9

After:
56p = Time after atomic energies summed: 99.3
120p = Time after atomic energies summed: 110.4

Almost 3X improvement on 120p.

I dont recall how much was due to the sched fix, but I remember that it was
significant.

Note that the amount of improvement is highly platform specific.

---

mh

--
Martin Hicks Wild Open Source Inc.
mort@wildopensource.com 613-266-2296