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Date: Thu, 14 Jun 2001 00:19:29 +0200
From: "J . A . Magallon" <jamagallon@able.es>
To: Lista Linux-Kernel <linux-kernel@vger.kernel.org>
Subject: accounting for threads
Message-ID: <20010614001929.A1242@werewolf.able.es>
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Hi.

First, sorry if this is a glibc issue. Just chose to ask here first.

I want to know the CPU time used by a POSIX-threaded program. I have tried
to use getrusage() with RUSAGE_SELF and RUSAGE_CHILDREN. Problem:
main thread just do nothing, spawns children and waits. And I get always
0 ru_utime.

I guess it can be because of 2 things:

- RUSAGE_CHILDREN only works for fork()'ed children (although in linux threads
and processes are the same). Perhaps fork() sets some kind of flag in
clone() for accounting.

- AFAIK, linux puts an intermediate 'thread controller'. That controller
uses no CPU time, and RUSAGE_CHILDREN gets only the first children level.

Any suggestion to mesaure threads CPU time ? I can't manage only with
wall-time, because I'm not sure to have all the box just for me.
And I would like also to mesaure system time to evaluate contention.

TIA

-- 
J.A. Magallon                           #  Let the source be with you...        
mailto:jamagallon@able.es
Linux Mandrake release 8.1 (Cooker) for i586
Linux werewolf 2.4.5-ac13 #1 SMP Sun Jun 10 21:42:28 CEST 2001 i686