Re: [squid-users] Squid performance profiling

On 06/20/2013 02:00 AM, Ahmed Talha Khan wrote:

> My test methodology looks like this
>
> generator(apache benchmark)<------->squid<------>server(lighttpd)
...
> These results show that squid is NOT CPU bound at this point. Neither
> is it Network IO bound because i can get much more throughput when I
> only run the generator with the server. In this case squid should be
> able to do more. Where is the bottleneck coming from?

The "bottleneck" may be coming from your test methodology -- you are
allowing Squid to slow down the benchmark instead of benchmark driving
the Squid box to its limits. You appear to be using what we call a "best
effort" test, where the request rate is determined by Squid response
time. In most real-world environments concerned with performance, the
request rate does not decrease just because a proxy wants to slow down a
little.

When we want to find the bottleneck, we often tell Web Polygraph to
increase proxy load until things start to break. In this "persistent
load" mode, Polygraph does not allow the proxy to determine the request
rate. It keeps pounding the proxy [at the configured rate], just like
real users would. I do not know whether ab can do it, but I would not be
surprised if it can. <plug>Still, I would recommend that you use a
benchmarking tool designed to test proxies rather than origin servers
:-).</plug>

Cheers,

Alex.
Received on Fri Jun 21 2013 - 01:17:17 MDT