Connections on the varnishbox

Poul-Henning Kamp phk at
Fri Oct 26 11:58:09 CEST 2007

In message <ujrbqanfib4.fsf at>, =?iso-8859-1?Q?Dag-Erling_Sm=F8rg
rav?= writes:

>One thing the man page doesn't mention is that connections are
>assigned to pools by computing (fd % thread_pools), so increasing the
>number of pools will also increase the likelihood that a connection
>will remain on the overflow queue even if there are threads available
>in other pools.  I don't know where the cutoff is, but it's likely to
>be at or below sqrt(thread_pool_max).

In retrospect, I am not convinced that idea/implementation of
multiple thread pools is sufficiently sound.  Its one area that
we will have to impove somehow.

Under no circumstances should more than a few pools (< 5) be created.

Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.

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