On Wed, 16 Jun 2004 11:46:26 +0200 Martin Nilsson <martin_at_gneto.com> wrote: > Alexander Leidinger wrote: > > Now I need to know how to determine those properties on at least some > > Intel CPUs (e.g. P3 & P4). > > The more expensive intel processors also have L3 caches of 1-4MB. > Since intels processors are built with inclusive caches (data in L2 > cache is also present in L3) shouldn't the value used be that of the > largest cache be it L2 or L3? Does the L3 cache have the same associativity as the L2 cache in those cases? > How much effct on performance does a wrong cache size value have? I'm not very familiar with the cache coloring (I don't need to, to change the tuning from a kernel option to autotuning), but AFAIK it at least wouldn't hurt. The actual way of choosing the number of colors is wrong, it allocates more than the optimal number of colors. This isn't as bad as using less than the optimal number of colors (or no colors at all). So we wouldn't get bad performance compared to the actual way of tuning the coloring. Actually we can get better performance, since a lot of people don't know about the page coloring at all or how to tune it with the kernel option. I think it's beneficial to tune to the L3 cache size (if present), but let's give Alan the final words here... Bye, Alexander. -- I'm available to get hired (preferred in .lu). http://www.Leidinger.net Alexander _at_ Leidinger.net GPG fingerprint = C518 BC70 E67F 143F BE91 3365 79E2 9C60 B006 3FE7Received on Wed Jun 16 2004 - 08:17:18 UTC
This archive was generated by hypermail 2.4.0 : Wed May 19 2021 - 11:37:57 UTC