From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759684AbXLNGLe (ORCPT ); Fri, 14 Dec 2007 01:11:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752724AbXLNGLZ (ORCPT ); Fri, 14 Dec 2007 01:11:25 -0500 Received: from e31.co.us.ibm.com ([32.97.110.149]:41636 "EHLO e31.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751919AbXLNGLY (ORCPT ); Fri, 14 Dec 2007 01:11:24 -0500 From: Darren Hart Reply-To: Darren Hart Organization: IBM Linux Technology Center To: linux-rt-users@vger.kernel.org Subject: Using CONFIG_FUNCTION_TRACE Date: Thu, 13 Dec 2007 22:11:22 -0800 User-Agent: KMail/1.9.6 (enterprise 0.20070907.709405) Cc: "lkml, " MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200712132211.23003.dvhltc@linux.vnet.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org I was trying to use CONFIG_FUNCTION_TRACE with the example trace-it.c in linux/scripts. On both 2.6.23.9-rt13 and 2.6.24-rc2-rt1 the system slower becomes less responsive (measured by typing in ssh and a serial console) until after a couple minutes it doesn't respond to anything including sysrq, requiring a power cycle. The trace-it.c program defaults to 10 seconds of tracing, I even tried dropping that to 100 us in case it just added so much overhead that 10 seconds of idle turned into minutes. But the 100us sleep hung too. I tested on a 4 way (2x2) opteron. I enabled: CONFIG_EVENT_TRACE CONFIG_FUNCTION_TRACE Thanks, -- Darren Hart IBM Linux Technology Center Real-Time Linux Team