[BUG] IBM440GX works too slow under nfsroot

Eugene Surovegin ebs at ebshome.net
Mon Oct 25 11:16:54 EST 2004

On Fri, Oct 22, 2004 at 01:29:55AM -0700, Eugene Surovegin wrote:
> FWIW, I haven't seen any problems when testing my new EMAC driver with 
> 100Mb hub, maybe it's only 10Mb related.
> Anyway, this is first time I'm hearing about half duplex problems, 
> Matt just mentioned them on IRC to me.
> I'll try to do some tests this weekend, although I have to admit half 
> duplex doesn't seem very important these days, nevertheless, if this 
> can be fixed, we better do this :).

OK, I did some tests with 2.4.28-pre4, 2.6.9 & 2.6.9-emac (2.6.9 with 
my new EMAC driver). I used Ocotea rev.3 with 440GX rev.C (533MHz).

I can confirm I see some problems in 10HDX mode - there is visible 
slow down during system boot up (NFS root). Just after logging into 
system, nfsstat shows around 350 retransmits.

My 2.6.9-emac tree doesn't show this behavior, I see no visible 
slow-down and nfsstat shows 0 retransmits.

I tried some quick hacks for 2.6.9 driver but was unable to find 
settings which could help (my new driver was almost re-written from 
scratch and I did a lot of things differently).

For *adventurous*, this new EMAC driver is available as a patch against 
2.6.9 BK tree at http://kernel.ebshome.net/. Please, note, it's still 
project in progress and it lacks support for all new 440GX features 
(GigE, TAH, jumbo frames, EMAC2/EMAC3). This is NAPI version with 
correct (I hope) error handling, chip access etc. On Ebony I was able 
to route around 144Kpps. I plan to implement support for _some_ 440GX 
new features soon (during next month, hopefully).

If there is an interest, I can make a patch against current 2.4 BK 
tree, but this will take some time (I'm a little swamped right now).


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