[openib-general] Re: [PATCH] TX/RX_RING_SIZE as loadable parameters

[Talpey, Thomas]

At 04:45 PM 3/7/2006, Roland Dreier wrote:
>No, IPoIB can have arbitrarily many packets in flight.  It's just like
>any other layer 2 net device in that respect.

I thought UD has only a single-packet window in the qp context.

>There isn't much uniformity about this in drivers/net.
>
>Unfortunately, making the ring sizes settable per-interface leads to a
>lot of ugly option handling code.  Is it relly important, or can we
>get by with one per-module setting?

Well, it's only important if the code that's there works well. I thought
Shirley said it doesn't. Has anyone instrumented it for overruns and
drops, and watched it under load? That would tell us what to tweak.

I dunno, it's probably deferrable (with Shirley's queue changes) as long
as there's a way to diagnose it later.

Constants are pretty much never correct in networking code. And module
parameters are darn close to being constants.

Tom.