Poor #requests/second performance

Poul-Henning Kamp phk at phk.freebsd.dk
Mon Jun 1 19:58:00 CEST 2009

In message <4A241423.4090509 at zopyx.com>, Andreas Jung writes:

>Running Varnish 2.0.4 on a Debian installation (dual-core, 2.8 GHz).
>Apache-Bench gives me a performance of 500-600 requests/second against
>a cached HTML page - even with an almost empty VCL configuration file.
>Squid gives me about 4000 requests/second on the same cached page.
>What is the best approach for narrowing down the bottleneck?

Examining varnishstat to see what happens.

Varnish employs a kind of "slow-start" algorithm to thread creation
which does not play well with synthetic loads like ab.  Typically
you have to precreate a suitable number of threads to avoid dropped
requests while varnish ramps up.

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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