Re: [PATCH/RFC 0/11] Shared Policy Overview

[Lee Schermerhorn <Lee.Schermerhorn@hp.com>]

On Thu, 2007-06-28 at 18:41 -0700, Christoph Lameter wrote:
> On Wed, 27 Jun 2007, Lee Schermerhorn wrote:
> 
> > > 1. The use is lightweight and does not impact performance.
> > 
> > I agree that use of memory policies should have a net decrease in
> > performance.  However, nothing is for free.  It's a tradeoff.  If you
> > don't need policies or if they hurt worse than they help, don't use
> > them.  No performance impact.  If locality matters and policies help
> > more than they cost, use them.  
> 
> Wel the current situation seems to be better AFAIK. Why tradeoff 
> anything for less performance and more inconsistencies?

Firstly, the "current situation" is deficient for applications that I,
on behalf of our customers, care about.

Secondly, I disagree with the "more inconsistencies" bit, as we've
discussed.  

Finally, as far as trading off performance, we're still at the
theoretical stage here.  I don't recall that you've ever tried my
patches on one of your problematic workloads to show that it has any
negative impact.  I don't see any in my tests, but I don't have access
to systems of the size that you do.  

> 
> > Maybe.  or maybe something different.  Laudable goals, anyway.  Let's
> > discuss in the NUMA BOF.
> 
> Would be good. I keep failing to see the point of all of this.

Apparently so... :-(

Lee

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