From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id 4F1E39000BD for ; Sun, 25 Sep 2011 04:14:59 -0400 (EDT) Received: from d06nrmr1806.portsmouth.uk.ibm.com (d06nrmr1806.portsmouth.uk.ibm.com [9.149.39.193]) by mtagate2.uk.ibm.com (8.13.1/8.13.1) with ESMTP id p8P8Emww021184 for ; Sun, 25 Sep 2011 08:14:48 GMT Received: from d06av10.portsmouth.uk.ibm.com (d06av10.portsmouth.uk.ibm.com [9.149.37.251]) by d06nrmr1806.portsmouth.uk.ibm.com (8.13.8/8.13.8/NCO v10.0) with ESMTP id p8P8EkfI2723872 for ; Sun, 25 Sep 2011 09:14:48 +0100 Received: from d06av10.portsmouth.uk.ibm.com (loopback [127.0.0.1]) by d06av10.portsmouth.uk.ibm.com (8.14.4/8.13.1/NCO v10.0 AVout) with ESMTP id p8P8Ej4S013590 for ; Sun, 25 Sep 2011 02:14:46 -0600 Date: Fri, 23 Sep 2011 17:51:32 +0100 From: Stefan Hajnoczi Subject: Re: [PATCH v5 3.1.0-rc4-tip 8/26] x86: analyze instruction and determine fixups. Message-ID: <20110923165132.GA23870@stefanha-thinkpad.localdomain> References: <20110920115938.25326.93059.sendpatchset@srdronam.in.ibm.com> <20110920120127.25326.71509.sendpatchset@srdronam.in.ibm.com> <20110920171310.GC27959@stefanha-thinkpad.localdomain> <20110920181225.GA5149@infradead.org> <20110920205317.GA1508@stefanha-thinkpad.localdomain> <4E7C7353.50802@hitachi.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E7C7353.50802@hitachi.com> Sender: owner-linux-mm@kvack.org List-ID: To: Masami Hiramatsu Cc: Christoph Hellwig , Srikar Dronamraju , Peter Zijlstra , Ingo Molnar , Steven Rostedt , Linux-mm , Arnaldo Carvalho de Melo , Linus Torvalds , Hugh Dickins , Andi Kleen , Thomas Gleixner , Jonathan Corbet , Oleg Nesterov , Andrew Morton , Jim Keniston , Roland McGrath , Ananth N Mavinakayanahalli , LKML On Fri, Sep 23, 2011 at 08:53:55PM +0900, Masami Hiramatsu wrote: > (2011/09/21 5:53), Stefan Hajnoczi wrote: > > On Tue, Sep 20, 2011 at 02:12:25PM -0400, Christoph Hellwig wrote: > >> On Tue, Sep 20, 2011 at 06:13:10PM +0100, Stefan Hajnoczi wrote: > > But this should be solvable so it would be possible to use perf-probe(1) > > on a std.h-enabled binary. Some distros already ship such binaries! > > I'm not sure that we should stick on the current implementation > of the sdt.h. I think we'd better modify the sdt.h to replace > such semaphores with checking whether the tracepoint is changed from nop. I like this option. The only implication is that all userspace tracing needs to go through uprobes if we want to support multiple consumers tracing the same address. > Or, we can introduce an add-hoc ptrace code to perftools for modifying > those semaphores. However, this means that user always has to use > perf to trace applications, and it's hard to trace multiple applications > at a time (can we attach all of them?)... I don't think perf needs to stay attached to the processes. It just needs to increment the semaphores on startup and decrement them on shutdown. Are you going to attempt either of these implementations? Stefan -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: email@kvack.org