From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753070AbdARQcJ (ORCPT ); Wed, 18 Jan 2017 11:32:09 -0500 Received: from mga04.intel.com ([192.55.52.120]:26873 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752184AbdARQcI (ORCPT ); Wed, 18 Jan 2017 11:32:08 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.33,249,1477983600"; d="scan'208";a="55414761" Date: Wed, 18 Jan 2017 08:31:26 -0800 From: Andi Kleen To: Jiri Olsa Cc: Andi Kleen , acme@kernel.org, jolsa@kernel.org, linux-kernel@vger.kernel.org, mingo@kernel.org Subject: Re: [PATCH 07/11] perf, tools: Collapse identically named events in perf stat Message-ID: <20170118163126.GE5460@tassilo.jf.intel.com> References: <20170103150833.6694-1-andi@firstfloor.org> <20170103150833.6694-8-andi@firstfloor.org> <20170118124446.GE11946@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170118124446.GE11946@krava> User-Agent: Mutt/1.7.1 (2016-10-04) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > > % perf stat -a -e unc_c_llc_lookup.any sleep 1 > > > > Performance counter stats for 'system wide': > > > > 2,685,120 Bytes unc_c_llc_lookup.any > > > > 1.002648032 seconds time elapsed > > > if one of them is not supported, we get wrong output: I would argue the output is not incorrect, after all it is not supported if something is missing. Imagine this is run with an interval: If we changed the number of output lines based on some dynamic scheduling condition this could confuse post processing scripts or users. Some output records would be completely different than others. So marking everything merged in these cases is better and more consistent. It is also difficult to change and should be a rare condition. -Andi