[PATCH] ucc_geth: Move freeing of TX packets to NAPI context.

[Joakim Tjernlund]

Anton Vorontsov <avorontsov at ru.mvista.com> wrote on 25/03/2009 15:25:40:
> 
> On Wed, Mar 25, 2009 at 02:30:49PM +0100, Joakim Tjernlund wrote:
> > >>From 1c2f23b1f37f4818c0fd0217b93eb38ab6564840 Mon Sep 17 00:00:00 
2001
> > From: Joakim Tjernlund <Joakim.Tjernlund at transmode.se>
> > Date: Tue, 24 Mar 2009 10:19:27 +0100
> > Subject: [PATCH] ucc_geth: Move freeing of TX packets to NAPI context.
> >  Also increase NAPI weight somewhat.
> >  This will make the system alot more responsive while
> >  ping flooding the ucc_geth ethernet interaface.
> 
> Some time ago I've tried a similar thing for this driver, but during
> tcp (or udp I don't quite remember) netperf tests I was getting tx
> watchdog timeouts after ~2-5 minutes of work. I was testing with a
> gigabit and 100 Mbit link, with 100 Mbit link the issue was not
> reproducible.
> 
> Though, I recalling I was doing a bit more than your patch: I was
> also clearing the TX events in the ucce register before calling
> ucc_geth_tx, that way I was trying to avoid stale interrupts. That

Sure, but that is another patch I think.

> helped to increase an overall performance (not only responsiveness),
> but as I said my approach didn't pass the tests.
> 
> I don't really think that your patch may cause this, but can you
> try netperf w/ this patch applied anyway? And see if it really
> doesn't cause any issues under stress?

Ran this on my host against my target board:
 netperf -t UDP_RR  -H 192.168.1.16
 netperf -t UDP_STREAM -H 192.168.1.16
 netperf -t TCP_STREAM -H 192.168.1.16
 netperf -t TCP_SENDFILE -H 192.168.1.16
 netperf -t TCP_MAERTS -H 192.168.1.16
 netperf -t TCP_RR -H 192.168.1.16
 netperf -t TCP_CRR -H 192.168.1.16

Didn't notice any timeouts, but I only have 100Mbit interfaces.