From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754413AbYITN7z (ORCPT ); Sat, 20 Sep 2008 09:59:55 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751218AbYITN7r (ORCPT ); Sat, 20 Sep 2008 09:59:47 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:37963 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751058AbYITN7r (ORCPT ); Sat, 20 Sep 2008 09:59:47 -0400 Date: Sat, 20 Sep 2008 09:59:45 -0400 (EDT) From: Steven Rostedt X-X-Sender: rostedt@gandalf.stny.rr.com To: Sitsofe Wheeler cc: Peter Zijlstra , Ingo Molnar , Arjan van de Ven , linux-kernel@vger.kernel.org, lenb@kernel.org, astarikovskiy@suse.de Subject: Re: Reading EeePC900 battery info causes stalls (was Re: How how latent should non-preemptive scheduling be?) In-Reply-To: <48D4CC1B.7030708@yahoo.com> Message-ID: References: <48D4CC1B.7030708@yahoo.com> User-Agent: Alpine 1.10 (DEB 962 2008-03-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, 20 Sep 2008, Sitsofe Wheeler wrote: > > > I thought we had a wakeup latency tracer exacty like we have preempt and > > irq off latency tracers, Steve, where'd that go? > > I rebuilt my kernel after a make clean and wakeup was still not there. It > might be a good idea to modify the kernel documentation currently > provided with 2.6.27 if it has gone away for now (or document the extra > switches needed to turn it on if that's why it didn't show up for me)... The wake up tracing is CONFIG_SCHED_TRACER. If you do not see "wakeup" as one of the available tracers in available_tracers, then check your dmesg and see if you have CONFIG_FTRACE_STARTUP_TEST enabled. There was a known bug that would cause the wakeup tracing to fail the test. When a trace fails the startup test, it is disabled. -- Steve