From owner-freebsd-net@FreeBSD.ORG Wed Apr 19 00:00:58 2006 Return-Path: X-Original-To: freebsd-net@freebsd.org Delivered-To: freebsd-net@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0B9D116A400 for ; Wed, 19 Apr 2006 00:00:58 +0000 (UTC) (envelope-from sam@errno.com) Received: from ebb.errno.com (ebb.errno.com [69.12.149.25]) by mx1.FreeBSD.org (Postfix) with ESMTP id A237E43D45 for ; Wed, 19 Apr 2006 00:00:57 +0000 (GMT) (envelope-from sam@errno.com) Received: from [10.0.0.248] (trouble.errno.com [10.0.0.248]) (authenticated bits=0) by ebb.errno.com (8.13.6/8.12.6) with ESMTP id k3J00qEL081629 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-SHA bits=256 verify=NO); Tue, 18 Apr 2006 17:00:53 -0700 (PDT) (envelope-from sam@errno.com) Message-ID: <44457DB4.4030601@errno.com> Date: Tue, 18 Apr 2006 17:00:52 -0700 From: Sam Leffler User-Agent: Thunderbird 1.5 (X11/20060210) MIME-Version: 1.0 To: Mike Tancsa References: <200604180244.k3I2icZj076600@white.dogwood.com> In-Reply-To: Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Cc: freebsd-net@freebsd.org Subject: Re: crypto accelerators X-BeenThere: freebsd-net@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Networking and TCP/IP with FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 19 Apr 2006 00:00:58 -0000 Mike Tancsa wrote: > On Mon, 17 Apr 2006 16:44:38 -1000 (HST), in sentex.lists.freebsd.net > you wrote: > >> I've read here before (or maybe some other freebsd list) that cards >> like the Soekris 1401 don't gain as much as you'd expect due to moving >> packets to/from the card over the PCI bus. But the context is usually >> one of trying to encrypt packets to increase throughput. >> >> So the question is whether these cards, regardless of their affect on >> throughput, increase usable CPU cycles? I have several Soekris 1401 >> cards and am wondering if there would be any point to putting them >> into some machines that provide logins over ssh. These machines are >> generally pretty good spec, 2.4GHz+, 1GB RAM, Intel MBs, mostly >> on-board peripherals. > > > The only place I found it really helpful for ssh connections was on > our backup server where we had multiple inbound ssh connections (e.g. > 10+ at once sending dump piped through ssh) it kept the CPU > utilization down. If you have just one or two, it doesnt really > matter Unless you're doing lots of scp's it's unlikely ssh traffic is going to generate large packets so offloading the crypto won't be worthwhile (cost to setup the h/w op probably is higher than doing the op in s/w). This has been discussed previously; see for example my BSDCan 2003 paper. Sam