From: elbows@... (Nathan Weston)
Date: 2003-09-15T10:25:10+09:00
Subject: Re: Debugging garbage collection

Thanks, that sounds like just what I need. I'll give it a try.

Nathan

Joel VanderWerf <vjoel@PATH.Berkeley.EDU> wrote in message news:<3F64D69F.4070500@path.berkeley.edu>...
> Nathan Weston wrote:
> > I have a Ruby program that seems to be leaking memory -- in the sense
> > that objects which I think should be GCed aren't getting GCed (even if
> > I call GC.start).
> > Something must be keeping references to these objects, but I can't
> > figure out what.
> > 
> > Are there any tools to debug this problem? Some way to watch the GC in
> > operation, or to find references to a particular object (at runtime),
> > would be helpful.
> 
> You can patch gc.c and variable.c to give some information. See
> 
> http://redshift.sourceforge.net/debugging-GC/
> 
> The patches there are for 1.6.7 and 1.7.2, unfortunately. I haven't had 
> the need to update them.
> 
> What it gives you is a method you can call like:
> 
>    GC.reachability_paths(obj)
> 
> and it will return an array of arrays, each of which is a path starting 
> from some root reference in the interpreter, and ending with an object 
> that contains a reference to obj. The root references can be ruby 
> objects or can be references on the stack or in globals, and those are 
> reported in descriptive strings, like
> 
>    "frame <number>: <filename> line <number>"
>    "Ruby global <varname>"
>    "C global <varname>"