[eepro100] 82559 polling mode

Donald Becker becker@scyld.com
Wed Dec 18 12:40:02 2002

On Wed, 18 Dec 2002, wyb wrote:

> I'm implementing a linux firewall with three 82559 cards. But under
> heavy load, interrupt entering and leaving code consume too much cpu
> time.

Hmmm, make certain that you are right about what is taking the CPU time.
My measurements have indicated that most time is consumed in skbuff
allocation, not taking the interrupt.

> So I want to implement a polling mode.

Where are you going to get a timer tick that is fast enough?

> What I want to know is: if I disable 82559 from interrupting CPU, does
> it still generate interrupt bit in SCB status words? If not so, speedo_interrupt() would do nothing, and the upper polling
> code is of no use.

As of last night, this is suddenly much easier!

Intel just released a special abridged manual for the 82559 series on
sourceforge.  Yes, the same information that for years required a NDA is
now available for public download.

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