From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S267397AbUGNPRr (ORCPT ); Wed, 14 Jul 2004 11:17:47 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S267398AbUGNPRr (ORCPT ); Wed, 14 Jul 2004 11:17:47 -0400 Received: from fw.osdl.org ([65.172.181.6]:18385 "EHLO mail.osdl.org") by vger.kernel.org with ESMTP id S267397AbUGNPRq (ORCPT ); Wed, 14 Jul 2004 11:17:46 -0400 Date: Wed, 14 Jul 2004 08:17:37 -0700 From: Chris Wright To: Ravikiran G Thirumalai Cc: linux-kernel@vger.kernel.org, dipankar@in.ibm.com Subject: Re: [RFC] Lock free fd lookup Message-ID: <20040714081737.N1973@build.pdx.osdl.net> References: <20040714045345.GA1220@obelix.in.ibm.com> <20040714045640.GB1220@obelix.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5i In-Reply-To: <20040714045640.GB1220@obelix.in.ibm.com>; from kiran@in.ibm.com on Wed, Jul 14, 2004 at 10:26:42AM +0530 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org * Ravikiran G Thirumalai (kiran@in.ibm.com) wrote: > This makes use of the lockfree refcounting infrastructure (see earlier > posting today) to make files_struct.fd[] lookup lockfree. This is carrying > forward work done by Maneesh and Dipankar earlier. > > With the lockfree fd lookup patch, tiobench performance increases by 13% > for sequential reads, 21 % for random reads on a 4 processor pIII xeon. I'm curious, how much of the performance improvement is from RCU usage vs. making the basic syncronization primitive aware of a reader and writer distinction? Do you have benchmark for simply moving to rwlock_t? thanks, -chris -- Linux Security Modules http://lsm.immunix.org http://lsm.bkbits.net