From: Stephen Sykes <sdsykes@...>
Date: 2009-01-14T17:16:15+09:00
Subject: [ruby-core:21338] Re: [PATCH] Promising C coding techniques to reduce MRI's memory use

Brent,

Sorry, I should have mentioned, I'm running on an Intel Mac - you
assumed I was running on a PowerPC.

> If I understand you correctly, compiling with gcc and
>
>  -fno-omit-frame-pointer
>
> causes ruby crashes on PowerPC OSx.  Does it also
> cause crashing on Intel OSx?

I have no information on PowerPC, it certainly causes crashing on
Intel to compile with -fomit-frame-pointer.  Presumably
-fno-omit-frame-pointer works ok, I haven't tried it.

> Are these crashes happening whether or not
> the MBARI patches are applied or only after applying them?

Only after applying the patches.  With those same compile options and
regular ruby everything works normally.  The error when compiling
patched ruby looks like this:

gcc -O2 -fomit-frame-pointer -pipe -fno-common    -DRUBY_EXPORT  -L.
 main.o dmydln.o libruby-static.a -ldl -lobjc   -o miniruby
./lib/fileutils.rb:1165: [BUG] Bus Error
ruby 1.8.7 (2009-1-11 MBARI 7/0x2370 on patchlevel 72) [i686-darwin9.6.0]
make: *** [.rbconfig.time] Abort trap


Last evening I ran into the following issue with my recently compiled
ruby (which I had compiled with the -O3 options I gave before):

/usr/local/lib/ruby/site_ruby/1.8/rubygems/specification.rb:333: [BUG] Bus Error
ruby 1.8.7 (2009-1-11 MBARI 7/0x4370 on patchlevel 72) [i686-darwin9.6.0]
Abort trap

I recomplied with your suggested options of
-O2 -fno-stack-protector
and this problem went away.  Perhaps best to stick with these options for now.

> Could you post some (brief) PPC OSx benchmark results
> comparing runtime and peak process size before and after patching, taking
> care to build ruby with the same compiler options each time?

I can do this for intel OSX if you need?

Regards,
Stephen