Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 22 Feb 2002 14:06:10 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 22 Feb 2002 14:06:00 -0500 Received: from pc-62-31-92-140-az.blueyonder.co.uk ([62.31.92.140]:47846 "EHLO kushida.apsleyroad.org") by vger.kernel.org with ESMTP id ; Fri, 22 Feb 2002 14:05:44 -0500 Date: Fri, 22 Feb 2002 19:04:31 +0000 From: Jamie Lokier To: Alan Cox Cc: Dan Kegel , "linux-kernel@vger.kernel.org" , Zach Brown Subject: Re: is CONFIG_PACKET_MMAP always a win? Message-ID: <20020222190431.A16926@kushida.apsleyroad.org> In-Reply-To: <20020222180957.A16796@kushida.apsleyroad.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.5.1i In-Reply-To: ; from alan@lxorguk.ukuu.org.uk on Fri, Feb 22, 2002 at 06:40:01PM +0000 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Alan Cox wrote: > > > Overhead: kernel does a full memcpy of the packet body to get it > > > into the ring buffer, and my program does another to get it out. > > > > I had a look at this about a year ago, and it seems there is no method > > provided to read the packets without copying them, if you need them in > > user space. > > You can process them in the ring buffer. If you can't keep up then you > are screwed any way you look at it 8) That still doesn't avoid copying: af_packet copies the whole packet (if you want the whole packet) from the original skbuff to the ring buffer. -- Jamie - 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/