[ofa-general] Re: [PATCH 2/3][NET_BATCH] net core use batching

[Stephen Hemminger]

On Tue, 09 Oct 2007 13:43:31 -0700 (PDT)
David Miller <davem at davemloft.net> wrote:

> From: Andi Kleen <andi at firstfloor.org>
> Date: 09 Oct 2007 18:51:51 +0200
> 
> > Hopefully that new qdisc will just use the TX rings of the hardware
> > directly. They are typically large enough these days. That might avoid
> > some locking in this critical path.
> 
> Indeed, I also realized last night that for the default qdiscs
> we do a lot of stupid useless work.  If the queue is a FIFO
> and the device can take packets, we should send it directly
> and not stick it into the qdisc at all.
> 
> > If the data is just passed on to the hardware queue, why is any 
> > locking needed at all? (except for the driver locking of course)
> 
> Absolutely.
> 
> Our packet scheduler subsystem is great, but by default it should just
> get out of the way.

I was thinking why not have a default transmit queue len of 0 like
the virtual devices.

-- 
Stephen Hemminger <shemminger at linux-foundation.org>