Re: memory pools, 23stable3 on FreeBSD

From: Alejandro Ramirez <>
Date: Wed, 31 May 2000 09:24:33 -0500

> would you recommend turning memory pools in squid.conf off for better
> performance. I am running 23stable3 with 784 RAM on FreeBSD 4.0-stable.

Yes, definitely

Quote from

The meaning of ``swapping'' varies. On FreeBSD for example, swapping out is
implemented as unlocking upages, kernel stack, PTD etc for aggressive
pageout with the process. The only thing left of the process in memory is
the 'struct proc'. The FreeBSD paging system is highly adaptive and can
resort to paging in a way that is equivalent to the traditional swapping
style operation (ie: entire process). FreeBSD also tries stealing pages from
active processes in order to make space for disk cache. I suspect this is
why setting 'memory_pools off' on the non-NOVM squids on FreeBSD is reported
to work better - the VM/buffer system could be competing with squid to cache
the same pages. It's a pity that squid cannot use mmap() to do file IO on
the 4K chunks in it's memory pool (I can see that this is not a simple thing
to do though, but that won't stop me wishing. :-).
by John Line (

Received on Wed May 31 2000 - 08:29:55 MDT

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