From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752786Ab3IILh3 (ORCPT ); Mon, 9 Sep 2013 07:37:29 -0400 Received: from mx1.redhat.com ([209.132.183.28]:30145 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751934Ab3IILh2 (ORCPT ); Mon, 9 Sep 2013 07:37:28 -0400 Date: Mon, 9 Sep 2013 13:36:41 +0200 From: Jiri Olsa To: Peter Zijlstra Cc: linux-kernel@vger.kernel.org, Corey Ashford , Frederic Weisbecker , Ingo Molnar , Namhyung Kim , Paul Mackerras , Arnaldo Carvalho de Melo , Andi Kleen , David Ahern Subject: Re: [PATCHv2 00/25] perf tool: Add support for multiple data file storage Message-ID: <20130909113640.GA16401@krava.redhat.com> References: <1378031796-17892-1-git-send-email-jolsa@redhat.com> <20130909111749.GP31370@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20130909111749.GP31370@twins.programming.kicks-ass.net> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Sep 09, 2013 at 01:17:49PM +0200, Peter Zijlstra wrote: > On Sun, Sep 01, 2013 at 12:36:11PM +0200, Jiri Olsa wrote: > > hi, > > sending the support for multiple file storage. Initial > > RFC is here: > > http://marc.info/?l=linux-kernel&m=137408381902423&w=2 > > > > v2 changes: > > - reworked perf mmap size setup to be able to get > > the mmap size value easily later > > - added perf.data read/write test for v2 and v3 > > for both endianity > > - added record '-M time' support > > So this 0/n post seems to have forgotten to list the rationale for doing > all this.. here it is: This patchset is actually doing 3 essential things: 1) adds new perf data format version (v3) 2) adds class/object to handle perf data file 3) adds record '-M size' option ad 1) Along the way I realized it'd be much easier to have the format simplified. I ended up with just 'DATA' and 'FEATURES' sections making the file format more generic. The easier/generic format will be for example useful for the cpu hotplug notification (and maybe even for ftrace data files features?) The version 2 should be still readable by perf, while it produces data in version 3 from this patchset onwards. ad 2) I needed to unify perf data file handling to make the -M implementation clear. > > The only reason I wanted this is so that each thread can write its own > data. The current one file thing is an immense bottle-neck for big > machines. > I haven't considered the thread based storage yet, but I think having the simplified format and centralized file handling will only help. jirka