On Tue, 22 Oct 2002, Ben Greear wrote:

Actually, with the changes the way they are, if you have a backlog value
of 300, and the first NAPI driver reads 300 packets, then all the rest of the
NAPI drivers will just throw away packets because the max-backlog has
already been hit (if I understand things correctly).

The 300 is shared amongst all the drivers which have something on their
rx DMA. This is done on a roundrobin fashion.
Also all the drivers which are non-napi are given the same quota.

If we make the backlog big enough to handle a large burst of incomming
traffic w/out dropping them, then the first NAPI driver can hog a very
large amount of CPU because its budget is now huge.  The rest of
the devices in the poll loop will not be serviced in time, and will
drop packets (I saw this when testing out the 4-port tulip driver with
the NAPI patch).

I think you misunderstood. Look at the dev->weight.

cheers,
jamal