Re: TOE brain dump

"David S. Miller" [off-list ref] writes:

On Mon, 4 Aug 2003 16:24:33 -0300
Werner Almesberger [off-list ref] wrote:

quoted

Eric W. Biederman wrote:

quoted

There is one place in low latency communications that I can think
of where TCP/IP is not the proper solution.  For low latency
communication the checksum is at the wrong end of the packet.

That's one of the few things ATM's AAL5 got right.

Let's recall how long the IFF_TRAILERS hack from BSD :-)

Putting the variable length headers on the end of a packet?  Or
was that something other than RFC893?

I think IPv6 solves that much more cleanly by simply deleting them.

quoted

But in the end, I think it doesn't really matter.

I tend to agree on this one.

And on the transmit side if you have more than 1 pending TX frame, you
can always be prefetching the next one into the fifo so that by the
time the medium is ready all the checksum bits have been done.

For large data transmissions that happens.
 

In fact I'd be surprised if current generation 1g/10g cards are not
doing something like this.

Well at this point before I propose anything concrete I suspect I need
to profile some actual application and see how things go.  But from a
very latency sensitive perspective, I would be surprised if the
problem goes away with faster technology.

For now I am happy just to insert the peculiar thought that latency
across the entire cluster/lan is of great importance to some
applications.

Eric