From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263725AbUHBXQt (ORCPT ); Mon, 2 Aug 2004 19:16:49 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263769AbUHBXQt (ORCPT ); Mon, 2 Aug 2004 19:16:49 -0400 Received: from mx1.redhat.com ([66.187.233.31]:16537 "EHLO mx1.redhat.com") by vger.kernel.org with ESMTP id S263725AbUHBXQr (ORCPT ); Mon, 2 Aug 2004 19:16:47 -0400 Date: Mon, 2 Aug 2004 16:15:14 -0700 From: "David S. Miller" To: William Lee Irwin III Cc: linux-kernel@vger.kernel.org, rusty@rustcorp.com.au Subject: Re: [patchset] Lockfree fd lookup 0 of 5 Message-Id: <20040802161514.54f02f60.davem@redhat.com> In-Reply-To: <20040802210119.GS2334@holomorphy.com> References: <20040802101053.GB4385@vitalstatistix.in.ibm.com> <20040802165607.GN12308@parcelfarce.linux.theplanet.co.uk> <20040802130729.2dae8fd5.davem@redhat.com> <20040802210119.GS2334@holomorphy.com> X-Mailer: Sylpheed version 0.9.12 (GTK+ 1.2.10; sparc-unknown-linux-gnu) X-Face: "_;p5u5aPsO,_Vsx"^v-pEq09'CU4&Dc1$fQExov$62l60cgCc%FnIwD=.UF^a>?5'9Kn[;433QFVV9M..2eN.@4ZWPGbdi<=?[:T>y?SD(R*-3It"Vj:)"dP Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 2 Aug 2004 14:01:19 -0700 William Lee Irwin III wrote: > I've found unusual results in this area. e.g. it does appear to matter > for mapping->tree_lock for database workloads that heavily share a > given file and access it in parallel. The radix tree walk, though > intuitively short, is long enough to make the rwlock a win in the > database-oriented uses and microbenchmarks starting around 4x. Thanks for the data point, because I had this patch I had sent to Rusty for 2.7.x which ripped rwlocks entirely out of the kernel. We might have to toss that idea :-)