From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S264973AbUHCCFp (ORCPT ); Mon, 2 Aug 2004 22:05:45 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S264980AbUHCCFU (ORCPT ); Mon, 2 Aug 2004 22:05:20 -0400 Received: from holomorphy.com ([207.189.100.168]:10929 "EHLO holomorphy.com") by vger.kernel.org with ESMTP id S264973AbUHCCFI (ORCPT ); Mon, 2 Aug 2004 22:05:08 -0400 Date: Mon, 2 Aug 2004 19:04:59 -0700 From: William Lee Irwin III To: "David S. Miller" Cc: linux-kernel@vger.kernel.org, rusty@rustcorp.com.au Subject: Re: [patchset] Lockfree fd lookup 0 of 5 Message-ID: <20040803020459.GV2334@holomorphy.com> Mail-Followup-To: William Lee Irwin III , "David S. Miller" , linux-kernel@vger.kernel.org, rusty@rustcorp.com.au References: <20040802101053.GB4385@vitalstatistix.in.ibm.com> <20040802165607.GN12308@parcelfarce.linux.theplanet.co.uk> <20040802130729.2dae8fd5.davem@redhat.com> <20040802210119.GS2334@holomorphy.com> <20040802161514.54f02f60.davem@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20040802161514.54f02f60.davem@redhat.com> User-Agent: Mutt/1.5.6+20040523i 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. On Mon, Aug 02, 2004 at 04:15:14PM -0700, David S. Miller wrote: > 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 :-) In all honesty, I'd rather use RCU, but that's a little more work than most RCU conversions. -- wli