Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756746AbZDICLW (ORCPT ); Wed, 8 Apr 2009 22:11:22 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753070AbZDICLN (ORCPT ); Wed, 8 Apr 2009 22:11:13 -0400 Received: from cn.fujitsu.com ([222.73.24.84]:59544 "EHLO song.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-OK) by vger.kernel.org with ESMTP id S1752845AbZDICLM (ORCPT ); Wed, 8 Apr 2009 22:11:12 -0400 Message-ID: <49DD5964.8000803@cn.fujitsu.com> Date: Thu, 09 Apr 2009 10:11:48 +0800 From: Li Zefan User-Agent: Thunderbird 2.0.0.9 (X11/20071115) MIME-Version: 1.0 To: Ingo Molnar CC: Steven Whitehouse , Tom Zanussi , =?ISO-8859-1?Q?Fr=E9d=E9ric_Weisbecker?= , rostedt@goodmis.org, linux-kernel@vger.kernel.org, mingo@redhat.com, axboe@kernel.dk, Arnaldo Carvalho de Melo Subject: Re: Multiple Tracers References: <1239197703.3359.25.camel@localhost.localdomain> <20090408135312.GR18581@elte.hu> <1239199899.3359.39.camel@localhost.localdomain> <20090408142413.GF12931@elte.hu> In-Reply-To: <20090408142413.GF12931@elte.hu> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2365 Lines: 59 CC: Arnaldo Carvalho de Melo Ingo Molnar wrote: > * Steven Whitehouse wrote: > >> Hi, >> >> On Wed, 2009-04-08 at 15:53 +0200, Ingo Molnar wrote: >>> * Steven Whitehouse wrote: >>> >>>> Hi, >>>> >>>> A little while back I posted a RFC patch which added gfs2 glock >>>> tracing to blktrace. There was a suggestion that I should look >>>> instead at the generic tracing code and add a new tracer, but I've >>>> come up with a couple of issues along the way. >>>> >>>> I think from what I can see that its only possible to run a single >>>> tracer at once, so running blktrace (for example) would preclude >>>> me from also tracing gfs2's glocks at the same time. Also, I can >>>> see no mechanism by which I could ensure the sequencing between >>>> the blktrace and glock traces other than exporting the blktrace >>>> sequence number, even if running multiple tracers at the same time >>>> was possible. >>> There's a recent addition: the EVENT_TRACE() facility. Would that >>> suit your purposes? >>> >>> Ingo >> If I can get both blktrace and glock trace info from it, then yes. >> I thought that the blktrace output went either via the original >> relayfs path, or via its own tracer so that it wasn't possible to >> use it and the event trace facility at the same time, unless I use >> blktrace via relayfs. From what I've read I thought that probably >> the relayfs interface for blktrace might eventually be removed in >> favour of the generic tracing interface, but I'm not 100% sure of >> that, so perhaps someone can confirm the plans in that area? > > Tom Zanussi (Cc:-ed) recently converted the blktrace tracepoints to I guess you mean Arnaldo ;) > a tracing framework - and i think much of that could be reused to > add EVENT_TRACE() tracepoints to blktrace too. > > Tom, what's your take on this? > > In general, this is the direction we want to take: EVENT_TRACE() > tracepoints that can be used in a generic way, in any tracer. > Actually we've planed to do this, and for other tracers. -- Zefan -- 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/