From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Thu, 18 Jan 2001 06:04:48 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Thu, 18 Jan 2001 06:04:38 -0500 Received: from zeus.kernel.org ([209.10.41.242]:42712 "EHLO zeus.kernel.org") by vger.kernel.org with ESMTP id ; Thu, 18 Jan 2001 06:04:26 -0500 Message-ID: <3A66CDB1.B61CD27B@imake.com> Date: Thu, 18 Jan 2001 06:04:17 -0500 From: Russell Leighton Reply-To: leighton@imake.com X-Mailer: Mozilla 4.51 [en] (Win98; I) X-Accept-Language: en MIME-Version: 1.0 To: linux-kernel@vger.kernel.org Subject: Re: Is sendfile all that sexy? In-Reply-To: <200101181001.f0IA11I25258@webber.adilger.net> Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org "copy this fd to that one, and optimize that if you can" ... isn't this Larry M's "splice" (http://www.bitmover.com/lm/papers/splice.ps)? Andreas Dilger wrote: > Roger Wolff writes: > > I'd prefer an interface that says "copy this fd to that one, and > > optimize that if you can". > > > > For example, copying a file from one disk to another. I'm pretty sure > > that some efficiency can be gained if you don't need to handle the > > possibility of the userspace program accessing the data in between the > > read and the write. Sure this may not qualify as a "trivial > > optimization, that can be done with the existing infrastructure" right > > now, but programs that want to indicate "kernel, please optimize this > > if you can" can say so. > > Actually, this is a great example, because at one point I was working > on a device interface which would offload all of the disk-disk copying > overhead to the disks themselves, and not involve the CPU/RAM at all. > > I seem to recall that I2O promised something along these lines as well > (i.e. direct device-device communication). > > Cheers, Andreas > -- > Andreas Dilger \ "If a man ate a pound of pasta and a pound of antipasto, > \ would they cancel out, leaving him still hungry?" > http://www-mddsp.enel.ucalgary.ca/People/adilger/ -- Dogbert > - > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > Please read the FAQ at http://www.tux.org/lkml/ -- ------------------------------------------------- Russell Leighton leighton@imake.com http://www.247media.com Company Vision: To be the preeminent global provider of interactive marketing solutions and services. ------------------------------------------------- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/