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Date: Thu, 14 Mar 2002 02:08:34 -0500
From: Jakub Jelinek <jakub@redhat.com>
To: Dan Kegel <dkegel@ixiacom.com>
Cc: Ulrich Drepper <drepper@redhat.com>, 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)>
Message-ID: <20020314020834.Z2434@devserv.devel.redhat.com>
Reply-To: Jakub Jelinek <jakub@redhat.com>
In-Reply-To: <1016062486.16743.1091.camel@myware.mynet> <3C8FEC76.F1411739@ixiacom.com>
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In-Reply-To: <3C8FEC76.F1411739@ixiacom.com>; from dkegel@ixiacom.com on Wed, Mar 13, 2002 at 04:19:02PM -0800
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On Wed, Mar 13, 2002 at 04:19:02PM -0800, Dan Kegel wrote:
> 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?

Surely don't use timer for profiling.
Have the compiler generate profiling calls both at function entry and exit
and use rdtsc/whatever other register your machine has (or even better
profiling registers) to note time of that function being entered/left.

	Jakub
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