Subject: Re: Asynchronous crypto layer.

From: Michal Ludvig <[email-masked]>
Date: Sun, 31 Oct 2004 11:46:30 +0100

Evgeniy Polyakov wrote:
>
>>As he points out (and i am sure he can back it with data ;->), that
>>given the setup cost, packet size, algo and CPU and bus speed, it may
>>not make sense to use the chip at all ;->
>
> Michal has numbers - pure hardware beats soft in a certain setups
> in a fully synchronous schema, let's work SW and HW in parallel.

Yes, I have *some* numbers, but consider that they are for quite
eligible setup - encrypting ~1.5k IPsec packets. I should retry with a
much smaller MTU to see the difference...

I think it won't be the programmer but the system administrator who will
have to correctly set priorities and constraints for different
hardware/software engines for the particular system. With a slow CPU it
may be worth to offload even small blocks to hardware, with a fast one
it may be worth to set HW and SW as equal, etc.

Michal Ludvig
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SUSE Labs                    [email-masked]
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Personal homepage http://www.logix.cz/michal