Re: [PATCH 1/9] clockpro-nonresident.patch

Marcelo Tosatti
2006-01-01T02:58:40Z

On Sat, Dec 31, 2005 at 09:53:11AM -0500, Rik van Riel wrote:
> On Sat, 31 Dec 2005, Peter Zijlstra wrote:
>
> > > > +/*
> > > > + * For interactive workloads, we remember about as many non-resident pages
> > > > + * as we have actual memory pages. For server workloads with large inter-
> > > > + * reference distances we could benefit from remembering more.
> > > > + */
> > >
> > > This comment is bogus. Interactive or server loads have nothing to do
> > > with the inter reference distance. To the contrary, interactive loads
> > > have a higher chance to contain large inter reference distances, and
> > > many common server loads have strong locality.
> > >
> > > <snip>
> >
> > Happy to drop it, Rik?
>
> Sorry, but the comment is accurate.
>
> For interactive workloads you want to forget interreference
> distances between two updatedbs, even if mozilla didn't get
> used all weekend.
>
> OTOH, on NFS servers, or other systems with large interreference
> distances, you may _need_ to remember a larger set of non-resident
> pages in order to find the pages that are the hottest.
>
> In those workloads, the shortest inter-reference distance might
> still be larger than the size of memory...

Sure, for the few cases you describe here the comment is valid.

Happy new year!