From: Robert Klemme <shortcutter@...>
Date: 2012-09-11T15:27:09+09:00
Subject: Re: Looking for advice on how to report performance issues

On Mon, Sep 10, 2012 at 10:16 PM, jason marshall <jdmarshall@gmail.com> wrote:
> We have a Rails app running on Ruby 1.9.3, and a under Windows we're seeing
> a 20x time penalty in our RSpec tests.

And the hardware is comparable?

> I'm fairly new to Ruby, but not to performance analysis, so I've volunteered
> to follow up on this problem.  If I want to file/find a bug to associate
> with this problem, what sort of data should I be gathering, and how?

I have zero experience with Rails profiling, but maybe using the std
lib profiler can give you a first data point.

> Background/random data:
>
> We have 800+ tests, and on a good day they all run in a minute.  Some do no
> I/O (pure 'unit' test), most do light I/O (usually a couple create+reads to
> MongoDB or a render partial).  Only a few do any heavy lifting.
>
> I don't see any glaring hotspots.  Most of the tests seem to take several
> times longer to run.  Dots just accumulate slower.

Just to exclude an obvious issue: do you have an AV engine up and
running on the Windows box?  If yes, excluding some directories might
help.  Some engines then still slow down operation so completely
switching off for the test might also be an option to determine
whether it's AV.

To exclude something else: is there concurrent activity that eats CPU
and / or IO bandwidth?

Kind regards

robert

-- 
remember.guy do |as, often| as.you_can - without end
http://blog.rubybestpractices.com/