Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261220AbTEBEHV (ORCPT ); Fri, 2 May 2003 00:07:21 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261258AbTEBEHU (ORCPT ); Fri, 2 May 2003 00:07:20 -0400 Received: from zcars0m9.nortelnetworks.com ([47.129.242.157]:38616 "EHLO zcars0m9.nortelnetworks.com") by vger.kernel.org with ESMTP id S261220AbTEBEHU (ORCPT ); Fri, 2 May 2003 00:07:20 -0400 Message-ID: <3EB1F1CD.4060702@nortelnetworks.com> Date: Fri, 02 May 2003 00:19:25 -0400 X-Sybari-Space: 00000000 00000000 00000000 From: Chris Friesen User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:0.9.8) Gecko/20020204 X-Accept-Language: en-us MIME-Version: 1.0 To: Mark Mielke Cc: =?ISO-8859-1?Q?P=E5l?= Halvorsen , bert hubert , linux-kernel@vger.kernel.org Subject: Re: sendfile References: <20030430165103.GA3060@outpost.ds9a.nl> <20030430192809.GA8961@outpost.ds9a.nl> <20030430221834.GA23109@mark.mielke.cc> <20030501042831.GA26735@mark.mielke.cc> <3EB1A029.7080708@nortelnetworks.com> <20030502024147.GA523@mark.mielke.cc> 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 Content-Length: 1200 Lines: 31 Mark Mielke wrote: > As far as I understand, sendfile() still requires the data to get from the > disk to a page in memory, similar to how send() referencing an mmap()'d page > may cause a page fault, reading the data from disk to a page in memory. One > copy each. I don't know of a kernel interface that lets data be copied from > disk to ethernet card without involving a temporary copy to be in paged > memory at some point in time... perhaps the iSCSI stuff can do this? I dunno. According to this: http://asia.cnet.com/builder/program/dev/0,39009360,39062783,00.htm using sendfile() is easier on the CPU due to less trashing of the TLB. I do get your point about protocol limitiations though. Chris -- Chris Friesen | MailStop: 043/33/F10 Nortel Networks | work: (613) 765-0557 3500 Carling Avenue | fax: (613) 765-2986 Nepean, ON K2H 8E9 Canada | email: cfriesen@nortelnetworks.com - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/