Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753848AbdGLVcn (ORCPT ); Wed, 12 Jul 2017 17:32:43 -0400 Received: from mga06.intel.com ([134.134.136.31]:27973 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752363AbdGLVcl (ORCPT ); Wed, 12 Jul 2017 17:32:41 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.40,351,1496127600"; d="scan'208";a="992293098" Date: Wed, 12 Jul 2017 14:32:40 -0700 From: Andi Kleen To: Peter Zijlstra Cc: "Li, Aubrey" , Frederic Weisbecker , Christoph Lameter , Aubrey Li , tglx@linutronix.de, len.brown@intel.com, rjw@rjwysocki.net, tim.c.chen@linux.intel.com, arjan@linux.intel.com, paulmck@linux.vnet.ibm.com, yang.zhang.wz@gmail.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH v1 00/11] Create fast idle path for short idle periods Message-ID: <20170712213240.GE3441@tassilo.jf.intel.com> References: <20170710084647.zs6wkl3fumszd33g@hirez.programming.kicks-ass.net> <20170710144609.GD31832@tassilo.jf.intel.com> <20170710164206.5aon5kelbisxqyxq@hirez.programming.kicks-ass.net> <20170710172705.GA3441@tassilo.jf.intel.com> <20170711094157.5xcwkloxnjehieqv@hirez.programming.kicks-ass.net> <20170711160926.GA18805@lerouge> <20170711163422.etydkhhtgfthpfi5@hirez.programming.kicks-ass.net> <496d4921-5768-cd1e-654b-38630b7d2e13@linux.intel.com> <20170712083410.ualmvnvzoohyami5@hirez.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20170712083410.ualmvnvzoohyami5@hirez.programming.kicks-ass.net> 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: 678 Lines: 19 On Wed, Jul 12, 2017 at 10:34:10AM +0200, Peter Zijlstra wrote: > On Wed, Jul 12, 2017 at 12:15:08PM +0800, Li, Aubrey wrote: > > Okay, the difference is that Mike's patch uses a very simple algorithm to make the decision. > > No, the difference is that we don't end up with duplication of a metric > ton of code. What do you mean? There isn't much duplication from the fast path in Aubrey's patch kit. It just moves some code around from the cpuidle governor to be generic, that accounts for the bulk of the changes. It's just moving however, not adding. > It uses the normal idle path, it just makes the NOHZ enter fail. Which is only a small part of the problem. -Andi