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

From: David Miller <[email-masked]>
Date: Tue, 09 Oct 2007 13:43:31 -0700 (PDT)

From: Andi Kleen <[email-masked]>
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.