From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752572Ab1ARQWq (ORCPT ); Tue, 18 Jan 2011 11:22:46 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.123]:41935 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751781Ab1ARQWp (ORCPT ); Tue, 18 Jan 2011 11:22:45 -0500 X-Authority-Analysis: v=1.1 cv=UQuFHoD2CPQ248x8AXEbKhr4z9AaDqApxmEl3BhfZ64= c=1 sm=0 a=I98iFNk1EVwA:10 a=Q9fys5e9bTEA:10 a=OPBmh+XkhLl+Enan7BmTLg==:17 a=20KFwNOVAAAA:8 a=WsfaRA9WOQoGbdIM5TwA:9 a=Dgeb5pJwGuZ7ertf20gA:7 a=66UXReAZPk1K1ExzBbBE2UHAHEUA:4 a=PUjeQqilurYA:10 a=jEp0ucaQiEUA:10 a=OPBmh+XkhLl+Enan7BmTLg==:117 X-Cloudmark-Score: 0 X-Originating-IP: 67.242.120.143 Subject: Re: [PATCH] tracing: remove superfluous sub instructions From: Steven Rostedt To: Frederic Weisbecker Cc: Jiri Olsa , mingo@elte.hu, linux-kernel@vger.kernel.org In-Reply-To: <20110118155159.GA1791@nowhere> References: <1295364498-9288-1-git-send-email-jolsa@redhat.com> <20110118155159.GA1791@nowhere> Content-Type: text/plain; charset="ISO-8859-15" Date: Tue, 18 Jan 2011 11:22:42 -0500 Message-ID: <1295367762.12215.2.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.30.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 2011-01-18 at 16:52 +0100, Frederic Weisbecker wrote: > On Tue, Jan 18, 2011 at 04:28:18PM +0100, Jiri Olsa wrote: > > hi, > > > > I think there's no need for substracting MCOUNT_INSN_SIZE from the > > IP parameter before calling the function trace (/graph) handler. > > > > Maybe I overlooked something, but all the IP usage I saw ended > > up in the kallsyms_lookup function, which does the lookup using the > > functions' start/end boundaries to find the correct symbol for pointer. > > > > Thus it seems to me there's no point in substracting the > > MCOUNT_INSN_SIZE value from the IP parameter. > > > > I tested for x86_64 and got proper results, I believe it's > > the same case for x86_32. > > > > wbr, > > jirka > > > > > > Signed-off-by: Jiri Olsa > > Well, that sounds right after all. If we are only interested in the > symbol, the instruction that follows "call mcount" is still relevant > as it must belong to the same function. > > Steve? NAK, it will break function triggers/probes. The "func:traceon" and "func:traceoff". They compare the ip to the call location of mcount. -- Steve