Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757049AbZKWVZJ (ORCPT ); Mon, 23 Nov 2009 16:25:09 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756035AbZKWVZI (ORCPT ); Mon, 23 Nov 2009 16:25:08 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:34183 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755722AbZKWVZH (ORCPT ); Mon, 23 Nov 2009 16:25:07 -0500 Date: Mon, 23 Nov 2009 22:25:01 +0100 From: Ingo Molnar To: Frederic Weisbecker Cc: Arnaldo Carvalho de Melo , "K.Prasad" , LKML , Peter Zijlstra , Paul Mackerras Subject: Re: [PATCH 4/4] perf tools: Add support for breakpoint events in perf tools Message-ID: <20091123212501.GA18917@elte.hu> References: <1258987355-8751-1-git-send-email-fweisbec@gmail.com> <1258987355-8751-4-git-send-email-fweisbec@gmail.com> <20091123173601.GA7273@in.ibm.com> <20091123202525.GA4979@nowhere> <20091123210939.GD15547@ghostprotocols.net> <20091123211945.GC4979@nowhere> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20091123211945.GC4979@nowhere> User-Agent: Mutt/1.5.20 (2009-08-17) X-ELTE-SpamScore: -2.0 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.0 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.5 -2.0 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1102 Lines: 30 * Frederic Weisbecker wrote: > > Using just /proc/kallsyms all we can do is find the size of a > > variable by looking at its address and the address of the next one. > > > > - Arnaldo > > Hmm, but I worry a bit about alignment which would return us the wrong > size. > > May be can we first try to get the address from /proc/kallsyms, and if > we have dwarf, get the size from it, otherwise try some magic with > /proc/kallsysms... Can we extend /proc/kallsyms (or add /proc/kallsyms) to include a size field? Perhaps can we generate some sort of DSO-alike thing in /proc/vmlinux (via a default-off debug option in .config), that perf could just interpret the usual ELF way - which happens to be the symbol table of the kernel? It would use up some RAM, but it would also be quite useful for debugging purposes. Ingo -- 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/