mod_perl memory use on FreeBSD vs. Linux

[kyle dawkins <ky...@centralparksoftware.com>]

Hey guys

We just migrated our mod_perl servers from Linux to FreeBSD and so far 
it's been very successful (it's even working with DSO... go figure!).  
However, I have been noticing some different behaviour and I'm 
wondering if someone can enlighten me as to why it might be occurring.

Under Linux, our very-heavy mod_perl processes were reported as being 
about 30MB but with about 25MB is shared (lots of caching!).  Under 
FreeBSD, "top" only gives us "SIZE" and "RSS", which seem to be close 
to their Linux values, but I can't see the "SHARE" amount and I'm not 
100% sure how to find out exactly what it is, and with some simple 
arithmetic, it seems that under FreeBSD, it's sharing a lot less.  Has 
anyone else experienced this?  I find it really difficult to debug 
memeoiry problems on FreeBSD... anyone got any tips?  

Cheers

Kyle Dawkins
Central Park Software
http://www.centralparksoftware.com