Steve> Jes Sorensen wrote:
Jamie> A card that can be told "don't interrupt me for N us after
Jamie> receiving the next packet, unless you hit the high water mark"
Jamie> would be even better.
>> Thats exactly what some Gigabit Ethernet cards do.
Steve> A number of newer devices do this. It has benefits, but it has
Steve> a downside too. It imposes significant extra latency when there
Steve> is just a light load, which can hurt performance on
Steve> transactional traffic. A better scheme might be more like the
Steve> 16550 UART. Interrupt if you hit the high tide point, or the
Steve> wire goes quiet for a short while. Short here can mean very
Steve> short. This gives more interrupts under light load, when you
Steve> probably have plenty of spare CPU cycles to deal them. When the
Steve> load increases the interrupt rate drops. I haven't seen an
Steve> Ethernet chip which works in that way, but then I haven't
Steve> studied them all.
Thats exactly the situation Jamie explained, there is no difference.
Jes
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