Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760661AbWLJLK4 (ORCPT ); Sun, 10 Dec 2006 06:10:56 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1760666AbWLJLK4 (ORCPT ); Sun, 10 Dec 2006 06:10:56 -0500 Received: from nf-out-0910.google.com ([64.233.182.190]:26816 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760663AbWLJLK4 (ORCPT ); Sun, 10 Dec 2006 06:10:56 -0500 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=GaqrA4CBWvEntjXw8jhy8L2/or/et2Yc43yVLwd09e/Oro0WH7ze4l9apH6IFJBjVudWOa9E8tYQx1HZRm+mAPdTijKPQ/mgAh3M6rE4D8KiRp77h4zC7Ue00zJgN3vHOAfwtZ/Mlv/OYOBMwsAUVAgPxjhfR56gaklmpqG1o3k= Message-ID: <40f323d00612100310v176ff03es73ceeb520d631e4b@mail.gmail.com> Date: Sun, 10 Dec 2006 12:10:54 +0100 From: "Benoit Boissinot" To: "Amit Choudhary" Subject: Re: [PATCH] [DISCUSS] Optimizing linux applications with the help of the kernel. Cc: "Linux Kernel" In-Reply-To: <464448.56474.qm@web55602.mail.re4.yahoo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <464448.56474.qm@web55602.mail.re4.yahoo.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1037 Lines: 31 On 12/10/06, Amit Choudhary wrote: > Hi All, > > I just had an idea for improving the performance of linux applications with some help from the > kernel. Let's say that I have to make a copy of a file. So, I read the input file into a buffer > and then write the buffer to the output file. > > In both these cases the same data is coming from kernel_to_user and then from user_to_kernel. If > this can be short-circuited, that is, from kernel_to_kernel then the performance can be increased > a lot. > > The psuedocode would be: > > fd_inp = open _output_file > fd_out = open _input_file > instruct_kernel to write next data read from fd_inp to fd_out > read fd_out > > I think you are describing the splice syscall: see http://lwn.net/Articles/178199/ regards, Benoit - 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/