From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752996AbdJKSss (ORCPT ); Wed, 11 Oct 2017 14:48:48 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:46961 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751532AbdJKSsp (ORCPT ); Wed, 11 Oct 2017 14:48:45 -0400 Date: Wed, 11 Oct 2017 20:48:40 +0200 From: Peter Zijlstra To: Waiman Long Cc: Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-arch@vger.kernel.org, Davidlohr Bueso , Dave Chinner Subject: Re: [PATCH v6 00/11] locking/rwsem: Rework rwsem-xadd & enable new rwsem features Message-ID: <20171011184840.3uomgj3hxxzernfd@hirez.programming.kicks-ass.net> References: <1507744922-15196-1-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1507744922-15196-1-git-send-email-longman@redhat.com> User-Agent: NeoMutt/20170609 (1.8.3) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Oct 11, 2017 at 02:01:51PM -0400, Waiman Long wrote: > # of Patches Reader Writer > Applied Locking Rate Locking Rate > ------------ ------------ ------------ > 0 5,155/ 5,155/ 5,155 5,154/248,852/346,281 > 7 5,696/ 5,697/ 5,698 113,500/215,826/320,872 > 8 4,827/ 5,047/ 5,215 4,826/176,797/284,069 > 9 211,276/ 509,712/1,134,007 4,894/221,839/246,818 > 11 884,513/1,043,989/1,252,533 9,604/ 11,105/ 25,225 > > It can be seen that rwsem changes from writer-preferring to > reader-preferring. A bit radically so, you almost starve the writers there. From mboxrd@z Thu Jan 1 00:00:00 1970 From: Peter Zijlstra Date: Wed, 11 Oct 2017 18:48:40 +0000 Subject: Re: [PATCH v6 00/11] locking/rwsem: Rework rwsem-xadd & enable new rwsem features Message-Id: <20171011184840.3uomgj3hxxzernfd@hirez.programming.kicks-ass.net> List-Id: References: <1507744922-15196-1-git-send-email-longman@redhat.com> In-Reply-To: <1507744922-15196-1-git-send-email-longman@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Waiman Long Cc: Ingo Molnar , linux-kernel@vger.kernel.org, x86@kernel.org, linux-alpha@vger.kernel.org, linux-ia64@vger.kernel.org, linux-s390@vger.kernel.org, linux-arch@vger.kernel.org, Davidlohr Bueso , Dave Chinner On Wed, Oct 11, 2017 at 02:01:51PM -0400, Waiman Long wrote: > # of Patches Reader Writer > Applied Locking Rate Locking Rate > ------------ ------------ ------------ > 0 5,155/ 5,155/ 5,155 5,154/248,852/346,281 > 7 5,696/ 5,697/ 5,698 113,500/215,826/320,872 > 8 4,827/ 5,047/ 5,215 4,826/176,797/284,069 > 9 211,276/ 509,712/1,134,007 4,894/221,839/246,818 > 11 884,513/1,043,989/1,252,533 9,604/ 11,105/ 25,225 > > It can be seen that rwsem changes from writer-preferring to > reader-preferring. A bit radically so, you almost starve the writers there.