Re: [Gnash-dev] oprofile difficulties, easy access to debuginfo, and other thoughts

[Bernie Innocenti]

El Tue, 13-10-2009 a las 22:57 -0600, Rob Savoye escribió:
>   Called from where ?

We couldn't find out, because symbols availability is a pre-requisite
for dumping the call graphs.

>  I don't have oprofile setup on my other Fedora 11 machine.

It's amazingly simple these days: just install the oprofile-gui rpm and
then run "sudo oprof_start". Of course you also need to install the
kernel-debuginfo and gnash-debuginfo. You probably also want
glib-debuginfo and gtk-debuginfo.

In oprof_start, enable call graphs and set the path to your elf vmlinux
image (/usr/lib/debug/lib/modules/2.6.31.1-56.fc12.x86_64/vmlinux in my
case).

Now point Firefox at a YouTube video (or whatever you'd like to profile)
and start the daemon. Let it collect stats for a few seconds, then stop
everything and save.

VERY IMPORTANT: remember to delete old collection data between each run
because otherwise new data get *appended* to the old one, leading to
very confusing behavior!


>  Memset() is often used to set a newly allocated buffer to zeros 
> to make debugging easier, but can also be a performance hog.

How do we turn off this behavior?  By defining NDEBUG?

(I wonder if Fedora builds everything with -DNDEBUG compiler flag... it
would buy a lot of performance in some cases).


>    When I build Gnash from source, I get debug symbols. So I can only 
> guess it's an issue with how the packages are built. Some experimental 
> RPM packages I built, includingg the debug info ones are at:
> http://www.getgnash.org/packages/snapshots/fedora/. These I built using 
> my own gnash.spec file (which is checked into Gnash trunk). This is the 
> first time I've heard any issues about the lack of debug symbols in the 
> debuginfo packages. Me, I don't install packages except for my own for 
> testing, which I build myself.

I think I got the debug symbols all right even from the Fedora rpm. The
problem was just with oprofile... as if gnash did something that would
break oprofile. Something like multi-threading, perhaps?


>    Try on which machine ? An XO 1.5, standard Fedora 11, or a Debian 
> machine ? I made a shot at compiling Gnash on an XO 1.5 machine, but get 
> too many dependency errors when trying to install the *-devel packages 
> Gnash needs. I assume I can build on my other Fedora 11 machine and just 
> copy the executables over like I used to do ?

I've been doing these tests on a regular Lenovo laptop with a Core2Duo
processor and a "regular" rawhide install.


>  Is the Gstreamer packages standard now, or are the

I think they're standard. Most of the ugly customizations that OLPC did
are finally gone.

-- 
   // Bernie Innocenti - http://codewiz.org/
 \X/  Sugar Labs       - http://sugarlabs.org/