Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754167AbaBQWsc (ORCPT ); Mon, 17 Feb 2014 17:48:32 -0500 Received: from terminus.zytor.com ([198.137.202.10]:34668 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754101AbaBQWs3 (ORCPT ); Mon, 17 Feb 2014 17:48:29 -0500 Message-ID: <53029167.4060109@zytor.com> Date: Mon, 17 Feb 2014 14:47:03 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: Waiman Long , Thomas Gleixner , Ingo Molnar , Arnd Bergmann CC: linux-arch@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org, Peter Zijlstra , Steven Rostedt , Andrew Morton , Michel Lespinasse , Andi Kleen , Rik van Riel , "Paul E. McKenney" , Linus Torvalds , Raghavendra K T , George Spelvin , Tim Chen , Daniel J Blueman , Alexander Fyodorov , Aswin Chandramouleeswaran , Scott J Norton , Thavatchai Makphaibulchoke Subject: Re: [PATCH v4 0/3] qspinlock: Introducing a 4-byte queue spinlock References: <1392669684-4807-1-git-send-email-Waiman.Long@hp.com> In-Reply-To: <1392669684-4807-1-git-send-email-Waiman.Long@hp.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/17/2014 12:41 PM, Waiman Long wrote: > v3->v4: > - Remove debugging code and fix a configuration error > - Simplify the qspinlock structure and streamline the code to make it > perform a bit better > - Add an x86 version of asm/qspinlock.h for holding x86 specific > optimization. > - Add an optimized x86 code path for 2 contending tasks to improve > low contention performance. > > v2->v3: > - Simplify the code by using numerous mode only without an unfair option. > - Use the latest smp_load_acquire()/smp_store_release() barriers. > - Move the queue spinlock code to kernel/locking. > - Make the use of queue spinlock the default for x86-64 without user > configuration. > - Additional performance tuning. > > v1->v2: > - Add some more comments to document what the code does. > - Add a numerous CPU mode to support >= 16K CPUs > - Add a configuration option to allow lock stealing which can further > improve performance in many cases. > - Enable wakeup of queue head CPU at unlock time for non-numerous > CPU mode. > > This patch set introduces a queue-based spinlock implementation that > can replace the default ticket spinlock without increasing the size > of the spinlock data structure. As a result, critical kernel data > structures that embed spinlock won't increase in size and breaking > data alignments. > This is starting to look good, so I have pulled it into tip:x86/spinlocks to start give it some testing mileage. -hpa -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/