sam at errno.com
Wed Apr 19 00:00:58 UTC 2006
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
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.
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