From mboxrd@z Thu Jan 1 00:00:00 1970 From: Yury Norov Subject: Re: [RFC PATCH 0/3] arm64: queued spinlocks and rw-locks Date: Thu, 13 Apr 2017 13:33:09 +0300 Message-ID: <20170413103309.GA1875@yury-N73SV> References: <1491860104-4103-1-git-send-email-ynorov@caviumnetworks.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from mail-co1nam03on0085.outbound.protection.outlook.com ([104.47.40.85]:14752 "EHLO NAM03-CO1-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1750746AbdDMKdX (ORCPT ); Thu, 13 Apr 2017 06:33:23 -0400 Content-Disposition: inline In-Reply-To: Sender: linux-arch-owner@vger.kernel.org List-ID: To: Adam Wallis Cc: linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Arnd Bergmann , Peter Zijlstra , Catalin Marinas , Will Deacon , Ingo Molnar , Jan Glauber , jason.low2@hp.com On Wed, Apr 12, 2017 at 01:04:55PM -0400, Adam Wallis wrote: > On 4/10/2017 5:35 PM, Yury Norov wrote: > > The patch of Jan Glauber enables queued spinlocks on arm64. I rebased it on > > latest kernel sources, and added a couple of fixes to headers to apply it > > smoothly. > > > > Though, locktourture test shows significant performance degradation in the > > acquisition of rw-lock for read on qemu: > > > > Before After > > spin_lock-torture: 38957034 37076367 -4.83 > > rw_lock-torture W: 5369471 18971957 253.33 > > rw_lock-torture R: 6413179 3668160 -42.80 > > > > On our 48 core QDF2400 part, I am seeing huge improvements with these patches on > the torture tests. The improvements go up even further when I apply Jason Low's > MCS Spinlock patch: https://lkml.org/lkml/2016/4/20/725 It sounds great. So performance issue is looking like my local problem, most probably because I ran tests on Qemu VM. I don't see any problems with this series, other than performance, and if it looks fine now, I think it's good enough for upstream. Yury.