Re: RFC: issues concerning the next NAPI interface

Linas Vepstas
2007-08-24T16:51:39Z

On Fri, Aug 24, 2007 at 08:52:03AM -0700, Stephen Hemminger wrote:
>
> You need hardware support for deferred interrupts. Most devices have it (e1000, sky2, tg3)
> and it interacts well with NAPI. It is not a generic thing you want done by the stack,
> you want the hardware to hold off interrupts until X packets or Y usecs have expired.

Just to be clear, in the previous email I posted on this thread, I
described a worst-case network ping-pong test case (send a packet, wait
for reply), and found out that a deffered interrupt scheme just damaged
the performance of the test case. Since the folks who came up with the
test case were adamant, I turned off the defferred interrupts.
While defferred interrupts are an "obvious" solution, I decided that
they weren't a good solution. (And I have no other solution to offer).

--linas