From owner-freebsd-hackers@FreeBSD.ORG Fri Oct 6 10:55:44 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id A03E416A4D8; Fri, 6 Oct 2006 10:55:44 +0000 (UTC) (envelope-from rwatson@FreeBSD.org) Received: from cyrus.watson.org (cyrus.watson.org [209.31.154.42]) by mx1.FreeBSD.org (Postfix) with ESMTP id BE46743D46; Fri, 6 Oct 2006 10:55:41 +0000 (GMT) (envelope-from rwatson@FreeBSD.org) Received: from fledge.watson.org (fledge.watson.org [209.31.154.41]) by cyrus.watson.org (Postfix) with ESMTP id 595E646BF0; Fri, 6 Oct 2006 06:55:41 -0400 (EDT) Date: Fri, 6 Oct 2006 11:55:41 +0100 (BST) From: Robert Watson X-X-Sender: robert@fledge.watson.org To: Jochen Kaiser In-Reply-To: <20061005151536.GA25283@devil.rrze.uni-erlangen.de> Message-ID: <20061006115301.T43229@fledge.watson.org> References: <20061005151536.GA25283@devil.rrze.uni-erlangen.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed Cc: freebsd-hackers@freebsd.org, csjp@FreeBSD.org Subject: Re: libpcap perf improvement? latest ideas? X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 06 Oct 2006 10:55:44 -0000 On Thu, 5 Oct 2006, Jochen Kaiser wrote: > after reading a german master thesis [1] (dated 12/2004) about pcap > performance (with comparison of linux and freebsd) I searched freebsd > resources for pcap improvements. Unofortunately I did not find any > improvements like PF_RING and/or efforts for reducing the number of copy > operations from device to user space. > > Maybe I think too simple because I don't know how SMP fine locks are > influencing this (maybe it is very complex to improve that when you want to > avoid side effects.). > > Or maybe it is not important at all, because real applications use DAG > boards? > > I would appreciate any discussion here. > > greetings, > Jochen > > [1] www.net.in.tum.de/teaching/projects/docs/schneider_SEP_slides2.ps > [2] www.endace.com Quite a bit of work has been done on zero-copy for BPF, but none of it really commitable. Christian Peron (CC'd) and I have been talking about doing something that is commitable, but some of the details (such as memory ownership) are still very much up in the air. PF_RING takes an interesting approach, and one we should look at, but we'd also like to keep all the benefits of BPF rather than discard them, so need to consider how best to apply elements of the approach in our context. I'd like to see something like this happen for FreeBSD 7.0, with a possible backport if it goes really well. :-) Robert N M Watson Computer Laboratory University of Cambridge