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Date: Mon, 30 Mar 2009 12:24:01 -0400
Message-ID: <66887a3d0903300924n49897377qfffa642c65d72968@mail.gmail.com>
Subject: Re: Profiling live mod_perl backends
From: Perrin Harkins <pharkins@gmail.com>
To: Cosimo Streppone <cosimo@streppone.it>
Cc: Mod_perl users <modperl@perl.apache.org>
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On Mon, Mar 30, 2009 at 9:14 AM, Cosimo Streppone <cosimo@streppone.it> wrote:
> The problem that we had, this was in November last year,
> was that all the backends were at load 15.0-20.0 (normal was ~3-4)
> after an update to the application.

That's pretty rare (hitting a CPU problem), and it sounds severe
enough that your idea of automated stress tests before deployment
would work for catching it.

> While I try to get there, I thought it might be useful to dedicate 1 of the
> live backends to this "live profiling". Even if the application now is
> not having any problem, even at peak times.

Sure, give it a shot.  My suggestion would be to not collect too much
data before analyzing it though, at least at first.  Devel::NYTProf
can take a really long time if you feed it more than a few requests at
once.

- Perrin