From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753789AbaAJJgy (ORCPT ); Fri, 10 Jan 2014 04:36:54 -0500 Received: from merlin.infradead.org ([205.233.59.134]:54886 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751932AbaAJJgw (ORCPT ); Fri, 10 Jan 2014 04:36:52 -0500 Date: Fri, 10 Jan 2014 10:36:35 +0100 From: Peter Zijlstra To: Cody P Schafer Cc: Arnaldo Carvalho de Melo , Paul Mackerras , Ingo Molnar , LKML Subject: Re: [PATCH 2/3] perf: clarify comment regarding event merging Message-ID: <20140110093635.GI31570@twins.programming.kicks-ass.net> References: <1389311492-5059-1-git-send-email-cody@linux.vnet.ibm.com> <1389311492-5059-3-git-send-email-cody@linux.vnet.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1389311492-5059-3-git-send-email-cody@linux.vnet.ibm.com> User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 09, 2014 at 03:51:31PM -0800, Cody P Schafer wrote: > There are actually 2 things about software events that allow us to > merge them: they never fail to schedule _and_ they have transaction > handlers we can (and do, when they are added to !sw groups) ignore. Note > both of these in the comment on adding sw events to !sw groups. The latter is a direct consequence of the former. Since they can always be scheduled, they don't need any schedulability testing, and therefore the transaction stuff is useless.