From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S967396AbdADJmF (ORCPT ); Wed, 4 Jan 2017 04:42:05 -0500 Received: from merlin.infradead.org ([205.233.59.134]:38012 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S935784AbdADJl5 (ORCPT ); Wed, 4 Jan 2017 04:41:57 -0500 Date: Wed, 4 Jan 2017 10:41:49 +0100 From: Peter Zijlstra To: Waiman Long Cc: Ingo Molnar , linux-kernel@vger.kernel.org, Pan Xinhui , Boqun Feng Subject: Re: [PATCH v2] locking/pvqspinlock: Relax cmpxchg's to improve performance on some archs Message-ID: <20170104094149.GD25813@worktop.programming.kicks-ass.net> References: <1482697561-23848-1-git-send-email-longman@redhat.com> <20170103161836.GY3107@twins.programming.kicks-ass.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 03, 2017 at 05:07:54PM -0500, Waiman Long wrote: > On 01/03/2017 11:18 AM, Peter Zijlstra wrote: > > On Sun, Dec 25, 2016 at 03:26:01PM -0500, Waiman Long wrote: > >> A number of cmpxchg calls in qspinlock_paravirt.h were replaced by more > >> relaxed versions to improve performance on architectures that use LL/SC. > > Claim without numbers ;-) > > Well it is hard to produce actual numbers here as I don't have the setup > to gather data. Surely RHT has big PPC machines around? I know that getting to them is a wee bit of a bother, but they should be available somewhere.