From mboxrd@z Thu Jan 1 00:00:00 1970 From: Arnaldo Carvalho de Melo Subject: Re: perf record of multiple events: disable callgraph for some events Date: Fri, 9 Oct 2015 11:31:42 -0300 Message-ID: <20151009143142.GL14409@kernel.org> References: <4930261.j7GqdZnq15@agathebauer> <20151004204059.GF20515@kernel.org> <1795032.7YQzqPdcGP@agathebauer> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail.kernel.org ([198.145.29.136]:45398 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756110AbbJIObq (ORCPT ); Fri, 9 Oct 2015 10:31:46 -0400 Content-Disposition: inline In-Reply-To: <1795032.7YQzqPdcGP@agathebauer> Sender: linux-perf-users-owner@vger.kernel.org List-ID: To: Milian Wolff Cc: perf group Em Fri, Oct 09, 2015 at 04:08:10PM +0200, Milian Wolff escreveu: > On Sonntag, 4. Oktober 2015 17:40:59 CEST Arnaldo Carvalho de Melo wrote: > > Em Sun, Oct 04, 2015 at 01:48:21PM +0200, Milian Wolff escreveu: > > > would it be possible to add a feature to perf to only grab > > > callgraphs for a certain selection of events? E.g. thinking about > > > a lock contention profile of a Qt application, I'd listen to > > > -e syscalls:sys_enter_futex,syscalls:sys_exit_futex > > > Now, with the dwarf unwinder this easily produces huge data files in the > > > order of gigabytes. This cost could easily be reduced by a factor of two, > > > as one only needs the callgraphs for syscalls:sys_enter_futex - the TID > > > should be enough to find the callgraph for the enter event from the exit > > > trace point. > > > Could someone guide me in implementing such a feature to make it possible > > > to filter the events which trigger the collection of a callgraph? Or is > > > that already possible somehow? > > Can you please check if this suits you, it is already in the tree: > > > > commit e637d17757a10732fa5d573c18f20b3cd4d31245 > > Author: He Kuang > > Date: Mon Sep 28 03:52:16 2015 +0000 > > Perfect, Thanks Arnaldo for pointing me in that direction, and many thanks to > He for implementing it! Works like a charm. > > Does anyone have a suggestion on where to put documentation for this? I'll try > to add that then next week, together with the other stuff I've noticed and > couldn't find before. Otherwise, I'll put it into the docs for `perf record`'s > `--call-graph`. Works for me. Glad that it worked for you. :-) - Arnaldo