CentOS - Jul 2008 - Does sprof work on CentOS5?

No matter how I try, I can't seem to get a library profile from sprof on 
CentOS5.

Does anyone know if sprof actually works on CentOS5? I'd be very 
interested to hear if anyone is using it successfully.

At the moment I'm trying something like this to get the dump:

    LD_LIBRARY_PATH=. LD_PROFILE=libmy.so ./mymain

where libmy.so is the library I want to profile, and mymain is the 
executable which links to it.

This appears to create the profile dump successfully (which appears at 
/var/tmp/libmy.so.profile), but when I try to get a readable profile 
using sprof it fails:

    $ sprof libmy.so /var/tmp/libmy.so.profile
    sprof: failed to load shared object `libmy.so'

I have a CentOS4 machine here, and doing the above on that works fine, 
but I've had no luck at all on CentOS5 (all currently up-to-date).

Can anyone help? (Please!)

On Wed, Jul 9, 2008 at 1:57 PM, Hywel Richards <hywelbr at googlemail.com>
wrote:
>   LD_LIBRARY_PATH=. LD_PROFILE=libmy.so ./mymain
...
>   $ sprof libmy.so /var/tmp/libmy.so.profile
>   sprof: failed to load shared object `libmy.so'
Acutally I have no idea of what sprof is or does, but from the error
message above it seems sprof cannot find your library because it is
not in the default library search path. Try this:

$ LD_LIBRARY_PATH=.  sprof libmy.so /var/tmp/libmy.so.profile

Let us know how that goes.

HTH,
Filipe

Hywel Richards wrote:
> No matter how I try, I can't seem to get a library profile from sprof 
> on CentOS5.
>
> Does anyone know if sprof actually works on CentOS5? I'd be very 
> interested to hear if anyone is using it successfully.
>
> At the moment I'm trying something like this to get the dump:
>
>    LD_LIBRARY_PATH=. LD_PROFILE=libmy.so ./mymain
>
> where libmy.so is the library I want to profile, and mymain is the 
> executable which links to it.
>
> This appears to create the profile dump successfully (which appears at 
> /var/tmp/libmy.so.profile), but when I try to get a readable profile 
> using sprof it fails:
>
>    $ sprof libmy.so /var/tmp/libmy.so.profile
>    sprof: failed to load shared object `libmy.so'
>
> I have a CentOS4 machine here, and doing the above on that works fine, 
> but I've had no luck at all on CentOS5 (all currently up-to-date).
>
> Can anyone help? (Please!)
>
Given that I can get this to work well on a CentOS4 machine, and I have 
tried lots of minor trivial changes to command-line, etc, but still fail 
on CentOS5, does anyone know what I can do or where I can go to progress 
this further?

My current guess is that it is a (probably very trivial) bug, although I 
recognise there still the possibility that this is simply a usage 
problem (however, if that is so, the usage since centos4 has clearly 
changed).

A more straightforward program I might have a go at debugging, but I 
don't feel competent on this one - sprof is part of the glibc package.

The glibc pages (http://www.gnu.org/software/libc/bugs.html) say that 
bugs should be reported to the distribution project first.

I would also be interested to know what the general policy is regarding 
what to do about bugs on Centos. I presume there is no way for people 
involved in centos to make changes directly, otherwise the distribution 
stops being a clone, so bugs/fixes on the centos bugzilla presumably get 
fed back to redhat at some point, and then eventually trickle down? (Is 
there a webpage somewhere explaining how this works? I know the FAQ 
states that there is no relationship with redhat, but surely they must 
exploit the bug reports somehow).

Anyway, should I report this on the CentOS bugzilla?
Would someone take it up if I did?
I assume that reporting it to redhat would be inappropriate.
If not centos, should I go on to report it to glibc?

Hywel.