Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756024Ab0BXJFu (ORCPT ); Wed, 24 Feb 2010 04:05:50 -0500 Received: from mailout2.zih.tu-dresden.de ([141.30.67.73]:58636 "EHLO mailout2.zih.tu-dresden.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755570Ab0BXJFr convert rfc822-to-8bit (ORCPT ); Wed, 24 Feb 2010 04:05:47 -0500 Subject: Re: Patch for tracing c states (power_end) on x86 From: Robert =?ISO-8859-1?Q?Sch=F6ne?= To: Li Zefan Cc: Arjan van de Ven , Ingo Molnar , Thomas Gleixner , kernel list In-Reply-To: <4B84EAAE.5020408@cn.fujitsu.com> References: <1266999573.3415.8.camel@localhost> <4B84E51A.900@cn.fujitsu.com> <1267001084.3415.16.camel@localhost> <4B84EAAE.5020408@cn.fujitsu.com> Content-Type: text/plain; charset="UTF-8" Date: Wed, 24 Feb 2010 10:05:35 +0100 Message-ID: <1267002335.3415.21.camel@localhost> Mime-Version: 1.0 X-Mailer: Evolution 2.28.1 Content-Transfer-Encoding: 8BIT X-TUD-Virus-Scanned: mailout2.zih.tu-dresden.de Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5326 Lines: 159 I forgot to mention that I appended my original mail at the bottom of my previous one. Here it is: > ------------------------- Mail from Febr. 15th -------------------- > > Hi, > > I have a question regarding the event "power/power_end". > > For the standard linux kernel (2.6.32.8), it's just not reported - > > neither for the /sys/kernel/debug/tracing nor for the sys_perf_open > > approach. Reported means here: sampling events were not generated/there were no entries in debug/tracing. > > > > System: > > Intel Core 2 Quad, > > Kernel 2.6.32.8, > > for sys_perf_open:always using sampling counters, > > (Kernel 2.6.33-rcX should show the same behavior) > > > > After finding "my" c-state procedure in arch/x86/kernel/process.c > > (which was "static void mwait_idle(void)" btw), I added a > > trace_power_end call on the correct line: > > ... > > else > > local_irq_enable(); > > } else > > ... > > -> > > ... > > else > > local_irq_enable(); > > trace_power_end(0); > > } else > > ... > > Now the event was reported on /sys/kernel/debug/tracing, but still not > > for sys_perf_open. > > > > Then I had the idea, that trace_power_end's argument should be the same > > as the 2nd argument of the previous power_start. > > > > That worked. > > > > However, things to be done are: add trace_power_end's to some > > process.c's procedures. > > > > > > Bye Robert > > > > -------------------------End of Mail of Febr. 15th -------------------- Am Mittwoch, den 24.02.2010, 17:00 +0800 schrieb Li Zefan: > Robert Schöne wrote: > > Hi, > > > > Please don't top posting. :) > > > I tried to pass 0 in "my" sleep routine "static void mwait_idle(void)" > > Which led to the following behaviour: > > The event was reported on /sys/kernel/debug/tracing, but still not > > for sys_perf_open. > > The event was not reported by sys_perf_open()? Could you be more > elaborate on this? Because I don't get you here. > > > As 1 had been the argument which led to a working tracing, I assumed, > > that the argument should be the same as the 2nd arg of the last > > power_start event. > > Since this argument had been 1 in my case, it worked for me. However, 0 > > did not. > > > > Bye Robert > > > > > > > > Am Mittwoch, den 24.02.2010, 16:36 +0800 schrieb Li Zefan: > >> Robert Schöne wrote: > >>> Hello, > >>> > >>> Since noone replied to my last mail (Febr. 15th, 11:42), describing the > >>> way to fix the missing c-state tracing, here's a patch. > >>> Maybe its easier that way. > >>> > >>> (I used the perf-fixes-for-linus git tree to obtain a > >>> more-then-up-to-date version) > >>> > >>> Bye Robert > >>> > >>> > >>> diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c > >>> index 02d6780..b1cfb88 100644 > >>> --- a/arch/x86/kernel/process.c > >>> +++ b/arch/x86/kernel/process.c > >>> @@ -384,6 +384,7 @@ void default_idle(void) > >>> else > >>> local_irq_enable(); > >>> current_thread_info()->status |= TS_POLLING; > >>> + trace_power_end(1); > >>> } else { > >>> local_irq_enable(); > >>> /* loop is done by the caller */ > >>> @@ -451,6 +452,7 @@ void mwait_idle_with_hints(unsigned long ax, > >>> unsigned long cx) > >>> if (!need_resched()) > >>> __mwait(ax, cx); > >>> } > >>> + trace_power_end((ax>>4)+1); > >> The only argument of trace_power_end() is a dummy, so you can just > >> pass 0 or 1 to the trace hook, actually better pass 0 to be > >> consistent with other parts. > >> > >> The dummy argument can't be eliminated, because the macros that > >> automatically generates racing code have some limitations, and > >> seems it's not so easy to get over. > >> > >>> } > >>> > >>> /* Default MONITOR/MWAIT with no hints, used for default C1 state */ > >>> @@ -467,6 +469,7 @@ static void mwait_idle(void) > >>> __sti_mwait(0, 0); > >>> else > >>> local_irq_enable(); > >>> + trace_power_end(1); > >>> } else > >>> local_irq_enable(); > >>> } > >>> > >>> > >> -- > >> To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > >> the body of a message to majordomo@vger.kernel.org > >> More majordomo info at http://vger.kernel.org/majordomo-info.html > >> Please read the FAQ at http://www.tux.org/lkml/ > >> > > > > > > > > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/ > -- Robert Schoene Technische Universitaet Dresden Zentrum fuer Informationsdienste und Hochleistungsrechnen 01062 Dresden Tel.: (0351) 463-42483, Fax: (0351) 463-37773 E-Mail: Robert.Schoene@tu-dresden.de -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/