Interrupts + Polling mode (similar to Linux's NAPI)

[Barney Cordoba]

--- On Wed, 4/29/09, Luigi Rizzo <rizzo at iet.unipi.it> wrote:

> From: Luigi Rizzo <rizzo at iet.unipi.it>
> Subject: Re: Interrupts + Polling mode (similar to Linux's NAPI)
> To: "Erik Trulsson" <ertr1013 at student.uu.se>
> Cc: "Barney Cordoba" <barney_cordoba at yahoo.com>, "Andrew Snow" <andrew at modulus.org>, "FreeBSD Net" <freebsd-net at freebsd.org>
> Date: Wednesday, April 29, 2009, 9:57 AM
> On Wed, Apr 29, 2009 at 03:21:56PM +0200, Erik Trulsson
> wrote:
> > On Wed, Apr 29, 2009 at 05:46:32AM -0700, Barney
> Cordoba wrote:
> ...
> > > When the collective answer to better network
> performance is polling, it
> > > makes it appear as if the FreeBSD project is a
> bunch of dudes working on
> > > stuff they feel like doing, rather than there
> being some centralized plan
> > > to make the project successful.
> > 
> > That appearance is probably due to the fact the the
> FreeBSD project actually
> > is a bunch of dudes working on what they feel like
> doing (or in a few cases
> > on what they get paid for doing), and that there is
> very little centralized
> > planning being done. (And even if there was, there is
> no way of enforcing
> > that people work according to such a plan.)
> 
> not to mention that very little if any work has been done
> on polling recently: i developed the base system in
> 2001-2002,
> and since then there has been just some basic maintainance
> (at least in the tree).
> 
> cheers
> luigi

Obviously someone has ported it to 5, 6 and 7, and the pat answer to
performance questions about a driver is "have you tried polling"? Its
counterproductive and gives people an excuse not to create any mechanisms
to properly tune drivers and to write them correctly for SMP kernels.

Barney