From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 4951 invoked by alias); 17 Nov 2009 15:25:26 -0000 Received: (qmail 4939 invoked by uid 22791); 17 Nov 2009 15:25:23 -0000 X-SWARE-Spam-Status: No, hits=-2.5 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS X-Spam-Check-By: sourceware.org Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 17 Nov 2009 15:24:11 +0000 Received: from int-mx01.intmail.prod.int.phx2.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) by mx1.redhat.com (8.13.8/8.13.8) with ESMTP id nAHFOAJc031676 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=OK) for ; Tue, 17 Nov 2009 10:24:10 -0500 Received: from [10.11.8.114] (vpn-8-114.rdu.redhat.com [10.11.8.114]) by int-mx01.intmail.prod.int.phx2.redhat.com (8.13.8/8.13.8) with ESMTP id nAHFO7kB025012; Tue, 17 Nov 2009 10:24:08 -0500 Message-ID: <4B02C0A6.9030605@redhat.com> Date: Tue, 17 Nov 2009 15:25:00 -0000 From: Masami Hiramatsu User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.1.4pre) Gecko/20090922 Fedora/3.0-2.7.b4.fc11 Thunderbird/3.0b4 MIME-Version: 1.0 To: Ingo Molnar CC: Roland McGrath , lkml , systemtap , DLE Subject: Re: [PATCH -tip 3/3] Add get_signal tracepoint References: <20091113225226.15079.90813.stgit@harusame> <20091113225240.15079.4863.stgit@harusame> <20091113235333.0E3CC15E8@magilla.sf.frob.com> <20091114001020.GB24738@elte.hu> <4B01C95B.1070302@redhat.com> <20091117060130.GB30852@elte.hu> In-Reply-To: <20091117060130.GB30852@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-IsSubscribed: yes Mailing-List: contact systemtap-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Post: List-Help: , Sender: systemtap-owner@sourceware.org X-SW-Source: 2009-q4/txt/msg00553.txt.bz2 Ingo Molnar wrote: > > * Masami Hiramatsu wrote: > >>> - signal IPI/wakeup events >> >> All signals might be used for IPI, isn't it? :-) > > I mean, to analyze the various dynamic delivery details of how a signal > send affects a target task: > > 1) which task/PID was selected to be woken > > 2) if the task got woken (from sleep) due to the signal sending > > 3) if it was already woken, whether it needed an IPI via kick_process() Hmm, as far as I can see, some of these events can be caught by sched layer too. - trace_signal_send() will record target task. - wake_up_state() just calls try_to_wake_up(), and trace_sched_wakeup() will be called from it. - kick_process() might better have its own tracepoint. And also, I think signal_wake_up() might not be a good tracepoint for signal event, since there is no signr. Moreover some signal_wake_up() caller(e.g. recalc_sigpending*) silently wake up processes :-(. > What proportion of signals were wakeups and what proportion hit an > already running task is a relevant question to ask when analyzing the > performance characteristics of signals. Hmm, does it really require wakeup events in signal layer? I think that we can analyze the characteristics by combination of signal events and sched events. Thank you, -- Masami Hiramatsu Software Engineer Hitachi Computer Products (America), Inc. Software Solutions Division e-mail: mhiramat@redhat.com