How to determine the L2 cache size on non-AMD CPUs (automatic
page queue color tuning)?
Erich Dollansky
oceanare at pacific.net.sg
Wed Jun 16 10:18:21 GMT 2004
Hi,
Martin Nilsson wrote:
> Alexander Leidinger wrote:
>
> How much effct on performance does a wrong cache size value have?
>
The effect depends very much on the application and its ability to use
the CPU cache. I did some benchmarks to get a feeling for it on Athlon
MPs some time ago. The improvement in speed was up to factor 30 under
high CPU load for very data intense operations. Applications even could
become slower if the CPU cache holds the data anyway. The reason is the
additional effort to prefetch data which is already chached.
It is not this easy to use always the right strategy to get the right
data into the cache.
Erich
More information about the freebsd-current
mailing list