[vortex] 3c905C for a linux router

[Donald Becker]

On Fri, 8 Nov 2002, Ralph Doncaster wrote:

> I'm using a couple of 3c905C in a linux router.  Running 2.4.19 without
> firewalling and with large routing tables on a Duron 750 the box runs
> about 70% idle with ~60mbps of aggregate traffic and ~10K
> interrupts/sec.  With a flow of smaller packets giving ~50mbps and 15K
> interrupts/sec it was only ~40% idle.
> 
> I'm planning to rebuild the driver with rx_copybreak=0 to try to improve
> the performance with smaller packets.  The other thing I'd like to be able
> to do is rx interrupt mitigation like the Tulip 21143.   The driver only
> seems to support tx interrupt mitigation though.  Is there another driver
> I can use?

The 21143 interrupt mitigation is a hardware feature.

Deferring Rx interrupts requires hardware support.  While it's possible
to change the Rx interrupt setting to only interrupt with every second
or third packet, low rate traffic (imagine 'ping') will be unacceptably
delayed.

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