Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752243AbYLWTMe (ORCPT ); Tue, 23 Dec 2008 14:12:34 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751149AbYLWTMY (ORCPT ); Tue, 23 Dec 2008 14:12:24 -0500 Received: from moutng.kundenserver.de ([212.227.126.187]:52460 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751022AbYLWTMX (ORCPT ); Tue, 23 Dec 2008 14:12:23 -0500 Message-ID: <495137F4.9010404@vlnb.net> Date: Tue, 23 Dec 2008 22:11:48 +0300 From: Vladislav Bolkhovitin User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: =?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= CC: Steven Rostedt , Sam Ravnborg , linux-scsi@vger.kernel.org, James Bottomley , Andrew Morton , FUJITA Tomonori , Mike Christie , Jeff Garzik , Boaz Harrosh , Linus Torvalds , linux-kernel@vger.kernel.org, scst-devel@lists.sourceforge.net, Bart Van Assche , "Nicholas A. Bellinger" , Ingo Molnar Subject: Re: [PATCH][RFC 2/23]: SCST core References: <494009D7.4020602@vlnb.net> <49400ACD.3070502@vlnb.net> <20081210191213.GA15273@uranus.ravnborg.org> <49414DBE.6070801@vlnb.net> <20081211210917.GB27010@uranus.ravnborg.org> <4942BA85.3070408@vlnb.net> <1229118607.24995.18.camel@localhost.localdomain> <4943CAAB.4050008@vlnb.net> <494A37E9.5000009@vlnb.net> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 8bit X-Provags-ID: V01U2FsdGVkX18RMj/ZXVvvqKFnIb6SN4lmT5tY0xcN2ur+Vs+ UuaDN0PHX/NkJaDKnUbjTBNoZslDCUtDvdlEdIgoWM/zJJ3vC6 8Er5RFs15aD9SyqIxTuig== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2582 Lines: 62 Hi Fr?d?ric, Fr?d?ric Weisbecker, on 12/20/2008 04:06 PM wrote: > Hi Vladislav, > > 2008/12/18 Vladislav Bolkhovitin : >> Fr?d?ric Weisbecker, on 12/14/2008 03:35 AM wrote: >>> 2008/12/13 Vladislav Bolkhovitin : >>>> Also (maybe I simply miss something) looks like ftrace doesn't trace exit >>>> from functions, only entrance to them. Is it true? Is it possibly to log >>>> exit from functions as well? >>> That's true with 2.6.28, the function tracer traces on function entries >>> only. >>> But there is an add-on on ftrace which let one to trace on entry and >>> on return, the function >>> graph tracer. This tracer uses this facility to output a graph of >>> function calls and measure >>> the time elapsed during each function call. >>> You can also register two custom handlers to do some things you need >>> on entry and on return. >> Word "graph" is quite confusing. We don't need any graphs, we need a plain >> execution path tracing as in the attached example (this is what's currently >> done). > > The word graph is actually here to explain here that we not only trace > each function call > but we can actually retrieve all of the call path of a function and > then draw it as if it was > C code: > > 0) ! 108.528 us | } > 0) | irq_exit() { > 0) | do_softirq() { > 0) | __do_softirq() { > 0) 0.895 us | __local_bh_disable(); > 0) | run_timer_softirq() { > 0) 0.827 us | hrtimer_run_pending(); > 0) 1.226 us | _spin_lock_irq(); > 0) | _spin_unlock_irq() { > 0) 6.550 us | } > 0) 0.924 us | _local_bh_enable(); > 0) + 12.129 us | } > 0) + 13.911 us | } > 0) 0.707 us | idle_cpu(); > 0) + 17.009 us | } > 0) ! 137.419 us | } > 0) <========== | > 0) 1.045 us | } > 0) ! 148.908 us | } > 0) ! 151.022 us | } > 0) ! 153.022 us | } > 0) 0.963 us | journal_mark_dirty(); > 0) 0.925 us | __brelse(); Unfortunately, it lacks very useful "TASK-PID, CPU#, TIMESTAMP" header fields.. -- 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/