From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752765AbbGNVlP (ORCPT ); Tue, 14 Jul 2015 17:41:15 -0400 Received: from mga03.intel.com ([134.134.136.65]:15933 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751900AbbGNVlO (ORCPT ); Tue, 14 Jul 2015 17:41:14 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.15,474,1432623600"; d="scan'208";a="764477421" Message-ID: <55A581F9.3090507@linux.intel.com> Date: Tue, 14 Jul 2015 14:41:13 -0700 From: Dave Hansen User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.7.0 MIME-Version: 1.0 To: Oleg Nesterov CC: Jan Kara , Al Viro , Linus Torvalds , Paul McKenney , Peter Zijlstra , Daniel Wagner , Davidlohr Bueso , Ingo Molnar , Tejun Heo , linux-kernel@vger.kernel.org Subject: Re: [PATCH RFC 0/4] change sb_writers to use percpu_rw_semaphore References: <20150713212536.GA13855@redhat.com> <20150714104810.GB24369@quack.suse.cz> <20150714133731.GA24837@redhat.com> <55A57C50.1080406@linux.intel.com> <20150714212249.GA18441@redhat.com> In-Reply-To: <20150714212249.GA18441@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/14/2015 02:22 PM, Oleg Nesterov wrote: >> Using my little write-1-byte test (under will-it-scale), your 4 patches >> improves the number of writes/sec by 12%. My 3 patches improve the >> number of writes/sec by 32%. I looked at it again. I tested with this patch in addition to the ones modifying __sb_start/end_write(): https://lkml.org/lkml/2015/6/24/682 That is where the performance delta came from. Your patches (plus the fsnotify optimization) perform very similarly to my approach. Yours remove so much code that I think they are the preferable approach. They don't compile with lockdep on, btw. :)