William Lee Irwin III wrote:
>
> > William Lee Irwin III wrote:
> > >
> > > ...
> > > A 16KB or 64KB kernel allocation unit would then annihilate
> >
> On Fri, Dec 06, 2002 at 04:01:24PM -0800, Andrew Morton wrote:
> > You want to be careful about this:
> > CPU: L1 I cache: 16K, L1 D cache: 16K
> > Because instantiating a 16k page into user pagetables in
> > one hit means that it must all be zeroed. With these large
> > pagesizes that means that the application is likely to get
> > 100% L1 misses against the new page, whereas it currently
> > gets 100% hits.
>
> 16K is reasonable; after that one might as well go all the way.
16k will cause serious slowdowns.
> About the only way to cope is amortizing it by cacheing zeroed pages,
> and that has other downsides.
So will that. You've seen the kernbench profiles...
You will need to find a way to clear the page just before it
is used.
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This archive was generated by hypermail 2b29 : Sat Dec 07 2002 - 22:00:28 EST