Re: [PATCH] Reduce TLB flushing during process migration

[Martin Hicks <mort@wildopensource.com>]

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