Date: Tue, 18 Apr 2006 13:40:02 -1000 (HST) From: Dave Cornejo <dave@dogwood.com> To: Bruce M Simpson <bms@spc.org> Cc: freebsd-net@freebsd.org Subject: Re: crypto accelerators Message-ID: <200604182340.k3INe2Ep085862@white.dogwood.com> In-Reply-To: <20060418191015.GE28496@spc.org>
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> On Mon, Apr 17, 2006 at 04:44:38PM -1000, Dave Cornejo wrote: > > 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. > > Given that spec of machine, I don't see that a hardware cipher would > offer much improvement -- and some of the available crypto accelerators > don't perform Diffie-Helmann or AES, some do. > > I myself have a ubsec(4) card, and even when I hacked OpenSSH to use > OpenSSL engine support by default (with someone else's patch), I didn't > see that much improvement (even when I forced the use of MD5, RSA and > 3DES). > > I could be wrong though - the above is qualitative not quantitative. > > Regards, > BMS it sounds like you're thinking in terms of throughput and speed of the encrypted connections, which i agree probably won't see much of an improvement. but it would seem to me that doing the heavy math off-CPU reduces the amount of work the CPU does. are these saved CPU cycles available to someone who might be doing a compilation on this machine? Doug Ambriskos answer (thanks!) implies that maybe they are. thanks, dave c
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