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Date: Wed, 13 Mar 2002 16:19:02 -0800
From: Dan Kegel <dkegel@ixiacom.com>
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To: Ulrich Drepper <drepper@redhat.com>
CC: darkeye@tyrell.hu, libc-gnats@gnu.org, gnats-admin@cygnus.com, sam@zoy.org,
        Xavier Leroy <Xavier.Leroy@inria.fr>, linux-kernel@vger.kernel.org,
        babt@us.ibm.com
Subject: Re: libc/1427: gprof does not profile threads <synopsis of the problem  
 (one li\ne)>
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Ulrich Drepper wrote:
> 
> On Wed, 2002-03-13 at 15:17, Dan Kegel wrote:
> 
> > So let's break the logjam and fix glibc's linuxthreads' pthread_create
> > to [support profiling multithreaded programs]
> 
> I will add nothing like this.  The implementation is broken enough and
> any addition just makes it worse.  If you patch your own code you'll get
> what you want at your own risk.

OK.  What's the right way to fix this, then?

Here are a few alternate ideas off the top of my head:

* Rip out Linuxthreads, replace it with NGPT, and
start fixing from there?  (Or does NGPT already fix this?)

* Rewrite Linux's setitimer(ITIMER_PROF,...) to set up an 
interval timer for all threads of the thread group.

* Implement the profil() system call from Solaris
( http://ua1vm.ua.edu/cgi-bin/man-cgi?profil+2 )

What's your favorite idea for getting profiling of
multithreaded programs working on Linux?

Thanks,
Dan
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