[realtek] Question: Rx Ring Buffers in the rtl8139 module

Donald Becker becker@scyld.com
Fri Aug 30 14:38:01 2002


On Fri, 30 Aug 2002 joerg.beyer@email.de wrote:
> Donald Becker <becker@scyld.com> schrieb am 30.08.02 20:13:19:
> > On Fri, 30 Aug 2002 joerg.beyer@email.de wrote:
> > 
> > > 8139too gives in the order of 10.000 errors per sec under load, while
> > > rtl8139 is better and has (only) a few 100 errors per sec.
> > > 
> > > Is there anything I can do about that?
> > 
> > Turn on flow control, if you have a flow control switch.
> > Tune the PCI parameters.
> > 
> > What are the errors?  Dropped packets?  Or CRC errors?
> 
> dropped packet (ifconfig states the same sumber for dropped as
> for overruns). There are onyl Rx no Tx errors.

What are the errors reported in /proc/net/dev?

> Also nfs hangs after very few accesses: mounting a remote fs
> is ok, the first ls /mnt is often ok (but not always) and one of
> the next ls /mnt/somedir will hang.
> 
> > > It's an onboard NIC on a laptop.
> > 
> > Which might have a very slow PCI system or processor..
> 
> not really: it's a athlon 1200 mhz mobile. should be enough for a single
> TCP connection (my testcase is scp to the laptop).

It could still have a very slow PCI system.  The chip requires at least
a 25Mhz PCI clock, and reasonable bandwidth to main memory.

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
410 Severn Ave. Suite 210		Second Generation Beowulf Clusters
Annapolis MD 21403			410-990-9993