Varnish memory usage

Michael Lenaghan michaell at
Thu Jun 10 20:08:07 CEST 2010

> That's useful - how many threads and thread pools are you using?

Hello, Rich. I think the question was actually aimed at me...

I'm using:

    -h classic,333333
    -p listen_depth=2048
    -p thread_pools=1
    -p thread_pool_min=500
    -p thread_pool_max=500
    -p sess_timeout=600
    -p session_linger=0

(The hash table is bigger than I need at this point, but that's what
the test used.)

In other news: I ran the test on an Amazon m1.small instance type
("equivalent CPU capacity of a 1.0-1.2 GHz 2007 Opteron or 2007 Xeon
processor" with 1.7 GB of memory). In a separate performance test that
box could achieve ~6,000 RPS* on a tiny document (~128 B), or ~10,000
RPS if requests were pipelined. Large documents (> ~32 KB) could
saturate the network pipe (~80,000 KB/s) at a significantly lower RPS.
CPU utilization never exceeded ~38%, though there's a significant
discrepancy between the numbers reported by top and the numbers
reported by Amazon's CloudWatch.


*RPS means "requests per second," not "sessions per second." For what
we're doing I wasn't interested in measuring TCP connection overhead.

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