Re: PATCH 2.3.26: kmalloc GFP_ZERO
yodaiken@chelm.cs.nmt.edu
Tue, 9 Nov 1999 08:52:03 -0700
On Tue, Nov 09, 1999 at 05:17:30PM +0100, Jes Sorensen wrote:
> >>>>> "yodaiken" == yodaiken <yodaiken@chelm.cs.nmt.edu> writes:
>
> yodaiken> On Tue, Nov 09, 1999 at 03:07:12PM +0100, Jes Sorensen
> yodaiken> wrote:
> Mikulas> to do, it can clear free pages, and when GFP_ZERO request
> Mikulas> comes, it returns page directly without clearing overhead.
> >> Which I doubt is a win anyway, all you do is to sit there and
> >> thrash your cache in the background.
>
> yodaiken> PPC turns cache off and zeros during idle task. This is a
> yodaiken> major performance win. We measured.
>
> And Jakub just told us it wasn't a win under the same conditions on
> the Sparc64.
It depends on how you do it, on the architecture,
and on what you measure. Lmbench is an
invaluable hint, but it is not definitive. If kernel compiles speed
up by 20%, you knpw something.
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