From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754055AbYITVxc (ORCPT ); Sat, 20 Sep 2008 17:53:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751510AbYITVxY (ORCPT ); Sat, 20 Sep 2008 17:53:24 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:34975 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751490AbYITVxX (ORCPT ); Sat, 20 Sep 2008 17:53:23 -0400 Date: Sat, 20 Sep 2008 17:53:20 -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 , LKML , lenb@kernel.org, astarikovskiy@suse.de Subject: Re: Reading EeePC900 battery info causes stalls In-Reply-To: <48D52FE3.6060803@yahoo.com> Message-ID: References: <48D4CC1B.7030708@yahoo.com> <48D50498.5050608@yahoo.com> <48D52FE3.6060803@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: > Steven Rostedt wrote: > > OK, that is probably the known bug you are hitting. Simply disable the > > CONFIG_FTRACE_STARTUP_TEST and you should have the wakeup tracer. The bug is > > with the test, not the tracer, so it should not hurt you. > > Thanks - this made the wakeup tracer appear a you said. I have put two wakeup > traces up: > > http://sucs.org/~sits/test/eeepc-debug/20080920/latency_trace.txt.gz > http://sucs.org/~sits/test/eeepc-debug/20080920/trace.txt.gz > (each file is around 6Mbytes uncompressed) > > Here's a small extract of latency_trace.txt: > > > # tracer: wakeup > > # > > wakeup latency trace v1.1.5 on 2.6.27-rc6skw-dirty > > -------------------------------------------------------------------- > > latency: 3232905 us, #65620/6180619, CPU#0 | (M:desktop VP:0, KP:0, SP:0 Peter, these times are crazy, mainly due to the cpu_clock. He probably wants to use the sched_clock. Below is a patch to use it instead. Sitsofe, I notice that the trace states "desktop". This means that you are running with CONFIG_PREEMPT_VOLUNTARY. You want CONFIG_PREEMPT. [...] > > Is it intentional that the last event has a time earlier closer to that of the > first event? > Change the config, and see what you get with this patch: Note this is not compiled tested: --- kernel/trace/trace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) Index: linus.git/kernel/trace/trace.c =================================================================== --- linus.git.orig/kernel/trace/trace.c 2008-09-20 17:49:00.000000000 -0400 +++ linus.git/kernel/trace/trace.c 2008-09-20 17:49:35.000000000 -0400 @@ -60,7 +60,7 @@ ns2usecs(cycle_t nsec) cycle_t ftrace_now(int cpu) { - return cpu_clock(cpu); + return sched_clock(); } /* -- Steve