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On Jan 14, 2005, at 7:29 AM, Jesse Off wrote:

> I haven't heard of this "shoot-away" strategy.  How much performance is
> gained by not taking Tx interrupts?  How do you know when the Tx mbufs 
> can
> be freed?  It would be interesting to see some "ttcp" or "netperf"
> benchmarks so I could compare against the ep93xx enet driver/hardware.
> Here are some of the ep93xx numbers:

You can gain a lot of performance by not using Tx interrupts, on 
devices that can do it.

Basically, lazily/opportunistically GC the Tx descriptors e.g. once per 
second, when you get Rx interrupts, and when you run out of descriptors 
on the (*if_start)() routine.  Look at status bits in the pending 
descriptors.

         -- Jason R. Thorpe <thorpej@shagadelic.org>


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