Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753955Ab3FNWrQ (ORCPT ); Fri, 14 Jun 2013 18:47:16 -0400 Received: from mail-ie0-f180.google.com ([209.85.223.180]:41264 "EHLO mail-ie0-f180.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753846Ab3FNWrO (ORCPT ); Fri, 14 Jun 2013 18:47:14 -0400 MIME-Version: 1.0 In-Reply-To: <1371249104.1758.20.camel@buesod1.americas.hpqcorp.net> References: <1371165333.27102.568.camel@schen9-DESK> <1371167015.1754.14.camel@buesod1.americas.hpqcorp.net> <1371226197.27102.594.camel@schen9-DESK> <1371249104.1758.20.camel@buesod1.americas.hpqcorp.net> Date: Fri, 14 Jun 2013 15:47:13 -0700 Message-ID: Subject: Re: Performance regression from switching lock to rw-sem for anon-vma tree From: Michel Lespinasse To: Davidlohr Bueso Cc: Tim Chen , Ingo Molnar , Rik van Riel , Peter Zijlstra , Andrea Arcangeli , Mel Gorman , "Shi, Alex" , Andi Kleen , Andrew Morton , "Wilcox, Matthew R" , Dave Hansen , linux-kernel@vger.kernel.org, linux-mm Content-Type: text/plain; charset=ISO-8859-1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 852 Lines: 20 On Fri, Jun 14, 2013 at 3:31 PM, Davidlohr Bueso wrote: > A few ideas that come to mind are avoiding taking the ->wait_lock and > avoid dealing with waiters when doing the optimistic spinning (just like > mutexes do). > > I agree that we should first deal with the optimistic spinning before > adding the MCS complexity. Maybe it would be worth disabling the MCS patch in mutex and comparing that to the rwsem patches ? Just to make sure the rwsem performance delta isn't related to that. -- Michel "Walken" Lespinasse A program is never fully debugged until the last user dies. -- 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/