Xeon w/ L3 1MB cache vs Xeon w/o L3 cache

[Erich Dollansky]

Hi,

Simon wrote:

> Has anyone done any comparison to see if extra L3 cache on Xeon CPUs
> provides any benefit to FreeBSD's kernel/core services and various user
> services' (http/email/ftp/databases) performance? I read that L3 can make
> things slower instead of faster in cases where L3 is not utilized and the CPU
> is forced to access it anyway (when L1/L2 don't hold the data it wants),
> because it exists. Would anyone with personal experience with Xeon CPUs
> with and without L3 cache comment on the impact of L3 cache. Any links
> to any related articles would be appreciated, as well.
> 
I only have experience with other CPUs with L3 cache. L3 keeps 
them faster under high load conditions. It made a small negative 
impact under low load conditions because their L3 cache was much 
slower than their L1 and L2 caches.

If you have the high load it is worth the high price they cost.

I do not have any links for this. The work was done some time ago 
in a typical ISP environment. The tests included only FTP and 
database.

Erich