[PATCH 1/2]: powerpc/cell spidernet bottom half

Linas Vepstas linas at austin.ibm.com
Thu Aug 17 07:58:39 EST 2006

On Wed, Aug 16, 2006 at 01:46:40PM -0700, David Miller wrote:
> From: Jeff Garzik <jeff at garzik.org>
> Date: Wed, 16 Aug 2006 16:34:31 -0400
> > Linas Vepstas wrote:
> > > I was under the impression that NAPI was for the receive side only.
> > 
> > That depends on the driver implementation.
> What Jeff is trying to say is that TX reclaim can occur in
> the NAPI poll routine, and in fact this is what the vast
> majority of NAPI drivers do.

I'll experiment with this.  When doing, say, an ftp, there are 
enough TCP ack packets coming back to have NAPI netdev->poll 
be called frequently enough? 

> implied.  In fact, I get the impression that spidernet is limited
> in some way and that's where all the strange approaches are coming
> from :)

Hmm. Or maybe I'm just getting old. Once upon a time, low watermarks
were considered the "best" way of doing anything; never occurred to me
it would be considered "strange".  Based on my probably obsolete idea
of what constitutes "slick hardware", I was actually impressed by what
the spidernet could do.

Aside from cleaning up the transmit ring in the receive poll loop,
what would be the not-so-strange way of doing things?


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