From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754372AbcGTOeb (ORCPT ); Wed, 20 Jul 2016 10:34:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:35858 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754306AbcGTOeV (ORCPT ); Wed, 20 Jul 2016 10:34:21 -0400 Date: Wed, 20 Jul 2016 16:34:17 +0200 From: Jiri Olsa To: Nikolay Borisov Cc: Peter Zijlstra , "Linux-Kernel@Vger. Kernel. Org" , andi@firstfloor.org Subject: Re: Strange behavior of perf top with PEBS Message-ID: <20160720143417.GA25992@krava> References: <578F7C82.6090500@kyup.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <578F7C82.6090500@kyup.com> User-Agent: Mutt/1.6.2 (2016-07-01) X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.31]); Wed, 20 Jul 2016 14:34:20 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Jul 20, 2016 at 04:28:34PM +0300, Nikolay Borisov wrote: > Hello, > > Running perf version 4.4.14.g0cb188d (no modification to the PMU/perf > code) I observed that "perf top" counts no cycles and produces no > output. After a bit of head scratching and testing I figured that > running "perf top -e cycles" actually works whereas the default option > is equivalent to running "perf top -e cycles:p". So the latter version > seems to not work on my machine. hum, I think Core2 has PEBs valid only for instructions not cycles.. I'll check why perf top forcing the precise for cycles I thought we had that automated already jirka