From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754808Ab2EHNMN (ORCPT ); Tue, 8 May 2012 09:12:13 -0400 Received: from mail-vb0-f46.google.com ([209.85.212.46]:52019 "EHLO mail-vb0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753815Ab2EHNML (ORCPT ); Tue, 8 May 2012 09:12:11 -0400 Date: Tue, 8 May 2012 10:12:07 -0300 From: Arnaldo Carvalho de Melo To: David Ahern Cc: linux-kernel@vger.kernel.org, peterz@infradead.org Subject: Re: [PATCH] perf record: fix fallback to cpu-clock on ppc Message-ID: <20120508131207.GG2485@infradead.org> References: <1336452004-55724-1-git-send-email-dsahern@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1336452004-55724-1-git-send-email-dsahern@gmail.com> X-Url: http://acmel.wordpress.com 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 Em Mon, May 07, 2012 at 10:40:04PM -0600, David Ahern escreveu: > perf-record on PPC is not falling back to cpu-clock: > > Old kernel, cannot exclude guest or host samples. > > Error: sys_perf_event_open() syscall returned with 6 (No such device or address). /bin/dmesg may provide additional information. > > Fatal: No CONFIG_PERF_EVENTS=y kernel support configured? > > The problem is that until 2.6.37 (behavior changed with commit b0a873e) > perf on PPC returns ENXIO when hw_perf_event_init() fails. With this > patch we get the expected behavior: > > Old kernel, cannot exclude guest or host samples. > The cycles event is not supported, trying to fall back to cpu-clock-ticks > [ perf record: Woken up 1 times to write data ] > [ perf record: Captured and wrote 0.150 MB /tmp/perf.data (~6569 samples) ] Would be good to have this documented on the spot, i.e. just before that if. Also, have you checked that 'perf stat' and 'perf top' works as well? We really need to move all this logic to a central place, namely perf_evlist__open(). For now checking if stat and top ara ok should be enough. - Arnaldo > Signed-off-by: David Ahern > --- > tools/perf/builtin-record.c | 3 ++- > 1 files changed, 2 insertions(+), 1 deletions(-) > > diff --git a/tools/perf/builtin-record.c b/tools/perf/builtin-record.c > index 42e2414..080c708 100644 > --- a/tools/perf/builtin-record.c > +++ b/tools/perf/builtin-record.c > @@ -244,7 +244,8 @@ try_again: > * based cpu-clock-tick sw counter, which > * is always available even if no PMU support: > */ > - if (err == ENOENT && attr->type == PERF_TYPE_HARDWARE > + if ((err == ENOENT || err == ENXIO) > + && attr->type == PERF_TYPE_HARDWARE > && attr->config == PERF_COUNT_HW_CPU_CYCLES) { > > if (verbose) > -- > 1.7.5.4