Re: [squid-users] A very low level question regarding performance of helpers.

From: Alex Rousskov <rousskov_at_measurement-factory.com>
Date: Wed, 12 Feb 2014 15:40:16 -0700

On 02/09/2014 06:48 AM, Eliezer Croitoru wrote:
> I have helpers in all sort of languages and it seems to me that there is
> a limit that do exist on the interface between squid and the helpers by
> the nature of the code as code.

For sequential helpers, the throughput is a function of response time:

  requests per second = number of helpers / mean response time

where the response time is the time from the creation of the helper
request (by Squid) to the end of processing of the helper response (by
Squid). Thus, it includes overheads of all components participating in
helper transaction (Squid, helper, OS, etc).

For the so called concurrent helpers, the throughput ought to be
unlimited as long as you are willing to increase concurrency levels,
provide RAM, tolerate the response delays, etc. However, the above
formula works for concurrent helpers with a given concurrency level if
you replace "number of helpers" with "configured concurrency level
multiplied by the number of helpers".

There may also be some helper API implementation limitations that lower
the above theoretical limits, but I personally do not know of any
specific ones.

HTH,

Alex.
Received on Wed Feb 12 2014 - 22:40:37 MST

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