[vortex] Why so many IRQ/sec with 3c905c (Tornado) card?

[Donald Becker]

On Fri, 21 Jun 2002, Richard Ellis wrote:

> On my setup, the Tornado card maxes out at about 11.8 MB/sec of receive
> data, and while receiving at this rate, it's generating about 60000
> irq's/second.  That works out to about 206 bytes per interrupt.

What is the interrupt count per (Tx+Rx) packet?
There should be about one interrupt per packet, less under heavy load or
with short packets.

If you are sharing the IRQ line with other device the interrupt rate
is unpredictable, but should be less than the sum of the individual
interrupt rates due to coincidental sharing.

You can reduce the interrupt rate, at the cost of increased latency.

-- 
Donald Becker				becker@scyld.com
Scyld Computing Corporation		http://www.scyld.com
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