From: "M. Edward (Ed) Borasky" <znmeb@...>
Date: 2007-09-05T13:04:35+09:00
Subject: Re: Ruby is much slower on linux when compiled with --enable-pthread?

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Jeffrey 'jf' Lim wrote:
> On 9/5/07, M. Edward (Ed) Borasky <znmeb@cesmail.net> wrote:
>> What I would suggest is
>> compiling Ruby with profiling and seeing where in the Ruby interpreter
>> these calls are.
>>
> 
> any idea how you would do that? Don't see anything in the configure
> switches for compiling ruby (1.8.6)...
> 
> -jf
> 
> --
> In the meantime, here is your PSA:
> "It's so hard to write a graphics driver that open-sourcing it would not help."
>     -- Andrew Fear, Software Product Manager, NVIDIA Corporation
> http://kerneltrap.org/node/7228
> 
> 

Before you "configure", type

export CFLAGS='-g -pg'

Then do
./configure
make

as normal. You will have a profiling Ruby executable.

Every time you run the profiling Ruby interpreter, you will get a file
called "gmon.out" which contains a binary profile. Then run

export GPROF_PATH=/path/to/ruby/source
gprof /path/to/ruby/executable > profile.txt
gprof -A /path/to/ruby/executable > annotated-source.txt

The "profile.txt" will give a call-graph profile of Ruby executing your
script, and "annotated-source.txt" will have a source listing of Ruby
with execution counts for all the lines.

A word of warning -- this compiles with no optimization at all, and can
be much slower as Ruby compiled with optimization. The call graph should
be all you need to determine where the system call is coming from.

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