On Sat, 2004-10-30 at 17:24, Evgeniy Polyakov wrote:
> On Sat, 30 Oct 2004 13:56:31 -0700
> Eugene Surovegin <ebs@xxxxxxxxxxx> wrote:
> > OK, what about 64 byte packets? I'm not saying hw crypto is useless,
> > what I'm saying is it's not that obvious that having hw crypto will
> > help in _all_ situations.
> For such cases I offered "rate" or "speed" parameter in my first e-mail,
> but it can be implicitly implemented by queue length.
> With 1 big datflow of packets with high priority and little dataflow of
> packets with little priority if we will catch high priority packets by SW
> and thus can have situation when we will _never_ catch low-priority packets,
> with even very slow HW we can route all those low-priority packets into it,
> at least they will be processed sometimes...
Can you explain the "rate" or "speed" parameter ?
I havent studied your code, however, what Eugene is pointing out is
You should have in your queuing towards the crypto chip ability to
batch. i.e sort of nagle-like "wait until we have 10 packets/20KB or 20
jiffies" before you send everything in the queue to the chip.
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 ;->