Messages in this thread | | | Date | Wed, 05 Nov 2008 10:20:23 -0800 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH RFC/RFB] x86_64, i386: interrupt dispatch changes |
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Cyrill Gorcunov wrote: > > I see. Thanks! Btw Peter, I remember I read long time ago about > segment caches (well... in time of DOS programming actually). But > there was only 'common' words like this cache exist. But maybe > it's possible to know what exactly size of such a cache is? > You mentoined number 32. (heh... I hadn't remember it until > you mentoined about such a cache :-) >
As with any other caching structure, you can discover its size, associativity, and replacement policy by artificially trying to provoke patterns that produce pathological timings.
At Transmeta, at one time we used a 32-entry direct-mapped cache, which ended up with a ~96% hit rate on common Win95 benchmarks.
I should, however, make it clear that there are other alternatives for speeding up segment descriptor loading, and not all of them rely on a cache.
-hpa
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