From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751404AbaHMHZb (ORCPT ); Wed, 13 Aug 2014 03:25:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:13360 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750722AbaHMHZa (ORCPT ); Wed, 13 Aug 2014 03:25:30 -0400 Date: Wed, 13 Aug 2014 09:24:49 +0200 From: Jiri Olsa To: Andi Kleen Cc: linux-kernel@vger.kernel.org, namhyung@kernel.org, acme@kernel.org, mingo@kernel.org, peterz@infradead.org Subject: Re: Implement lbr-as-callgraph v9 Message-ID: <20140813072449.GA2370@krava.brq.redhat.com> References: <1406827029-7991-1-git-send-email-andi@firstfloor.org> <20140812135017.GB13247@krava.brq.redhat.com> <20140812205524.GF4120@two.firstfloor.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140812205524.GF4120@two.firstfloor.org> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 12, 2014 at 10:55:24PM +0200, Andi Kleen wrote: > On Tue, Aug 12, 2014 at 03:50:17PM +0200, Jiri Olsa wrote: > > On Thu, Jul 31, 2014 at 10:17:00AM -0700, Andi Kleen wrote: > > > > SNIP > > > > > v5: > > > - Rename functions > > > - Fix gtk build problem > > > - Fix crash without -g > > > - Improve error messages > > > - Improve srcline display in various ways > > > v6: > > > - Port to latest perf/core > > > v7: > > > - Really port to latest perf/core > > > v8: > > > - Rebased on 3.16-rc1 > > > v9: > > > - Forward ported to latest tip/perf/core > > > > > > Example output: > > > > > > % perf record -b -g ./tsrc/tcall > > > > Why do we need the '-g' in here.. '-b' should be enough right? > > I saw u fill the rest of the backtrace with callchain > > data (if needed), but thats not necessary right? > > Right now the callgraph processing needs -g to enable itself. > I didn't try to fix it so far because we likely use -g in these > situations where --branch-history is useful. > > If you think it's important it could be fixed I think. > > > > > > > > [ perf record: Woken up 1 times to write data ] > > > [ perf record: Captured and wrote 0.044 MB perf.data (~1923 samples) ] > > > % perf report --branch-history > > > > When I captured data like you above and run pure 'perf report' > > I did not get callchains displayed at all. > > > > Also using 'perf report --branch-history' enables filename:line > > suffix for callchain regardless of using '-b' for data capture > > That's fine isn't it? If the user specifies that option > they should have used -b. > > Or do you mean it should only do it for branch entries? > Right now the callgraph code doesn't distinguish between branch > entry and callgraph entry, so it can't know. my concern was that '--branch-history' is changing report output even if there's no branch data.. but thats minor one, the bigger one is this: > > When I captured data like you above and run pure 'perf report' > > I did not get callchains displayed at all. jirka