[rescue] SunFastEthernet questions

Skeezics Boondoggle skeezics at q7.com
Tue Sep 2 18:14:11 CDT 2003

On Tue, 2 Sep 2003, Jonathan C. Patschke wrote:
> On Tue, 2 Sep 2003, Phil Stracchino wrote:
> > Actually, I haven't had any problems with my Netgear switch and the U1,
> > the U30, or the E3000.  All three happily sync up 100megabit full-duplex
> > with no intervention on my part.
> I've tried 3Com SuperStack switches, Catalyst 29xx and 35xx switches,
> and Cabletron switches.  Yes, it'll negotiate at all of them, but you
> won't get -nearly- full throughput.  At least, I was never able to.

The only troubles I've had with the hme's was with the Catalyst 5x00
series; the 35xx series and most other smaller boxes I've tried work fine.  
I've had more trouble with "le" interfaces and Ciscos than with the happy
meal cards.  (Rather than go fiddle with port settings, it's easier to
just stick a cheap 5-port hub in between when Jumpstarting older sun4[md]
boxes with "le" interfaces.  A hack, but it works.)

As for throughput, I've regularly pegged hme interfaces (Sbus, PCI or
on-board) with NFS traffic with a NetApp at the other end, both when
testing with 'bonnie' or even just in normal use.  Where you'll notice the
hme starts to fall down is when the packet rate gets up around 40,000/sec.
Maybe that's a driver issue, or maybe it's just the way interrupts are
handled; Sun "ge" Gigabit cards seem to do > 40K packets/sec without much
trouble in 'ttcp' tests.  Be sure to look at the recommended ndd tweaks
(setting send & receive windows, etc) to tune an hme for heavy TCP loads.  
They're in the Sun docs...

-- Chris

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