From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263533AbTJBWo0 (ORCPT ); Thu, 2 Oct 2003 18:44:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263532AbTJBWo0 (ORCPT ); Thu, 2 Oct 2003 18:44:26 -0400 Received: from e2.ny.us.ibm.com ([32.97.182.102]:958 "EHLO e2.ny.us.ibm.com") by vger.kernel.org with ESMTP id S263533AbTJBWoY (ORCPT ); Thu, 2 Oct 2003 18:44:24 -0400 Date: Thu, 02 Oct 2003 15:45:13 -0700 From: Hanna Linder Reply-To: Hanna Linder To: insecure@mail.od.ua, Jeff Garzik cc: Larry McVoy , Andrew Morton , Hanna Linder , lse-tech@lists.sourceforge.net, linux-kernel@vger.kernel.org Subject: Re: Minutes from 10/1 LSE Call Message-ID: <73350000.1065134713@w-hlinder> In-Reply-To: <200310030138.34430.insecure@mail.od.ua> References: <37940000.1065035945@w-hlinder> <200310022156.49678.insecure@mail.od.ua> <3F7C780C.9040001@pobox.com> <200310030138.34430.insecure@mail.od.ua> X-Mailer: Mulberry/2.2.1 (Linux/x86) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Ahh. I see the confusion. These are excerpts from two different speakers. Notice the line of ===== separating speakers in the minutes. This part is from Steve Pratt's mm vs mainline comparisons: > On Thursday 02 October 2003 22:10, Jeff Garzik wrote: >> insecure wrote: >> > That sounds reasonable, but today's RAM throughput is on the order >> > of 1GB/s, not 100Mb/s. 'Out of L1' theory can't explain 100Mb/s ceiling >> > it seems. >> >> cp(1) data, at least, will never ever be in L1. Copying data you need >> to look at the ends of the pipeline -- hard drive throughput, PCI bus >> bandwidth, FSB bandwidth, speed at which ext2/3 allocates blocks, and >> similar things are likely bottlenecks. > > Hmm. > This part is from Mark Gross's Real Time Application issues discussion: > On Wednesday 01 October 2003 22:19, Hanna Linder wrote: >> We got about 100 mb/sec using the bonie benchmark for block io writes, >> for writes we hit a ceiling around 100-120 mb/sec. Stopped scaling >> after about 3 spindles. >> >> Tried to focus on the block io part of it. Have not tried >> direct or raw io yet. With block IO we got about 133 mb/sec >> doing a simple dd to dev/null from multiple spindles. This >> was on the 2.6 test 3. >> .... >> Odirect on large block sizes has low cpu utilization ( 3-5% ). >> However with buffered IO we can easily get to 100% cpu utilization. >> If you look at the profile most of that is in the copy_to_user function. > > So: > * we hit a ceiling of ~133 Mb/s, no matter how many disks > * CPU utilization is 100%, spent mostly in copy_to_user > * RAM bandwidth is >1Gb/s Hanna