Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752924AbdFUBGl (ORCPT ); Tue, 20 Jun 2017 21:06:41 -0400 Received: from mail.kernel.org ([198.145.29.99]:44962 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752665AbdFUBGk (ORCPT ); Tue, 20 Jun 2017 21:06:40 -0400 DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3677E2395F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=acme@kernel.org Date: Tue, 20 Jun 2017 22:06:35 -0300 From: Arnaldo Carvalho de Melo To: Mark Wielaard Cc: Milian Wolff , Ravi Bangoria , Paolo Bonzini , linux-kernel@vger.kernel.org, "Naveen N. Rao" , linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v2] perf: libdw support for powerpc [ping] Message-ID: <20170621010635.GK13640@kernel.org> References: <1496312681-20133-1-git-send-email-pbonzini@redhat.com> <1497354282.3755.201.camel@klomp.org> <59400ADD.4090709@linux.vnet.ibm.com> <3621613.kMnvz8Tm3d@milian-kdab2> <1497525392.3755.307.camel@klomp.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1497525392.3755.307.camel@klomp.org> X-Url: http://acmel.wordpress.com User-Agent: Mutt/1.8.0 (2017-02-23) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1605 Lines: 44 Em Thu, Jun 15, 2017 at 01:16:32PM +0200, Mark Wielaard escreveu: > On Thu, 2017-06-15 at 10:46 +0200, Milian Wolff wrote: > > Just a quick question: Have you guys applied my recent patch: > > > > commit 5ea0416f51cc93436bbe497c62ab49fd9cb245b6 > > Author: Milian Wolff > > Date: Thu Jun 1 23:00:21 2017 +0200 > > > > perf report: Include partial stacks unwound with libdw > > > > So far the whole stack was thrown away when any error occurred before > > the maximum stack depth was unwound. This is actually a very common > > scenario though. The stacks that got unwound so far are still > > interesting. This removes a large chunk of differences when comparing > > perf script output for libunwind and libdw perf unwinding. > > > > If not, then this could explain the issue you are seeing. > > Thanks! No, I didn't have that patch (*) yet. It makes a huge > difference. With that, Paolo's patch and the elfutils libdw powerpc64 > fallback unwinder patch, it looks like I get user stack traces for > everything now on ppc64le. Can I take that as a Tested-by: you? - Arnaldo > Cheers, > > Mark > > (*) It just this one-liner, but what a difference that makes: > > --- a/tools/perf/util/unwind-libdw.c > +++ b/tools/perf/util/unwind-libdw.c > @@ -224,7 +224,7 @@ int unwind__get_entries(unwind_entry_cb_t cb, void *arg, > > err = dwfl_getthread_frames(ui->dwfl, thread->tid, frame_callback, ui); > > - if (err && !ui->max_stack) > + if (err && ui->max_stack != max_stack) > err = 0; > > /*