From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263459AbTJBTKa (ORCPT ); Thu, 2 Oct 2003 15:10:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263460AbTJBTKa (ORCPT ); Thu, 2 Oct 2003 15:10:30 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:19846 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S263459AbTJBTK3 (ORCPT ); Thu, 2 Oct 2003 15:10:29 -0400 Message-ID: <3F7C780C.9040001@pobox.com> Date: Thu, 02 Oct 2003 15:10:04 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.4) Gecko/20030703 X-Accept-Language: en-us, en MIME-Version: 1.0 To: insecure@mail.od.ua 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 References: <37940000.1065035945@w-hlinder> <20031001233815.GB29605@work.bitmover.com> <3F7B701C.5020708@pobox.com> <200310022156.49678.insecure@mail.od.ua> In-Reply-To: <200310022156.49678.insecure@mail.od.ua> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org 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. You'll never hit RAM bandwidth limits, unless your copies are extremely tiny, and entirely in L2 or pagecache. Jeff