Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757386Ab3J1Rs1 (ORCPT ); Mon, 28 Oct 2013 13:48:27 -0400 Received: from out4-smtp.messagingengine.com ([66.111.4.28]:38952 "EHLO out4-smtp.messagingengine.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756848Ab3J1Rs0 (ORCPT ); Mon, 28 Oct 2013 13:48:26 -0400 X-Sasl-enc: gXiCg77vakj439Jk6nw2gEhDrKNFxVPyp5YsDCCQOGnc 1382982505 Message-ID: <526EA366.4020204@iki.fi> Date: Mon, 28 Oct 2013 19:48:22 +0200 From: Pekka Enberg User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.6; rv:24.0) Gecko/20100101 Thunderbird/24.0.1 MIME-Version: 1.0 To: Srikar Dronamraju CC: Masami Hiramatsu , Hemant Kumar , LKML , Peter Zijlstra , Oleg Nesterov , hegdevasant@linux.vnet.ibm.com, Ingo Molnar , anton@redhat.com, systemtap@sourceware.org, Namhyung Kim , aravinda@linux.vnet.ibm.com Subject: Re: [PATCH v4 2/3] Support for perf to probe into SDT markers: References: <20131023044511.1886.82571.stgit@hemant-fedora> <20131023050502.1886.15779.stgit@hemant-fedora> <526E4940.8000608@hitachi.com> <526E5BA5.7050103@iki.fi> <20131028141152.GA1040@linux.vnet.ibm.com> <526E72EC.9060400@iki.fi> <20131028173152.GB1040@linux.vnet.ibm.com> In-Reply-To: <20131028173152.GB1040@linux.vnet.ibm.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1825 Lines: 49 On 10/28/13 7:31 PM, Srikar Dronamraju wrote: >>> But what if a system has both 32 bit libc and 64 bit libc? >>> Wont we could end up with 2 libc:setjmp? >>> Should we give some more intelligence into perf to choose the 64 bit >>> libc over 32 bit one? >> You can just trace both of them by default, no? >> > There has to be a one to one association with the event name and its > mapping. Every event name will finally map to a unique inode and an > offset. > > One option would be for perf to look at these markers and have a > different event name for similar markers in different executables. I think we are talking past each other here. Yes, I understand that you need an fully qualified name for a SDT marker but there's absolutely no reason to force feed that to the user of 'perf trace'. For the 32-bit and 64-bit libc case, why cannot 'perf list' by default print out something like: $ perf list libc:setjmp [SDT marker group] and provide a '--fully-qualified' command line option that: $ perf list --fully-qualified libc:setjmp => libc32:setjmp, libc64:setjmp [SDT marker group] libc32:setjmp => libc:setjmp@/lib/libc.so.6 [SDT marker] libc64:setjmp => libc:setjmp@/lib64/libc.so.6 [SDT marker] and then teach 'perf trace' to deal with SDT marker groups where you trace two events, not one? And again, there's no reason to treat system libraries like libc the same way as some random binary in $HOME. You can use the fully qualified name in 'perf list' for things that are not in /lib or some perf-specific whitelist. Pekka -- 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/