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Date: Wed, 26 Dec 2007 19:10:21 +0800
From: Erich Dollansky <oceanare@pacific.net.sg>
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To: Jordi Espasa Clofent <jordi.espasa@opengea.org>
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Cc: freebsd-net@freebsd.org
Subject: Re: Maximum NIC interrupts
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Hi,

Jordi Espasa Clofent wrote:
> 
> I want to say that I'm don't know if 8000 irq per second means a high 
> IRQ use or a lower user.

I must say, that I did not do hardware since some time. But 10 000 
Interrupts per second is not this high. Modern CPUs should be able to 
handle much much more.

So, the limit will be the operating system and the driver's ability to 
finish its job before the next interrupt comes.

Enabling polling helps with slower CPUs.

The maximum possible interrupt rate is given by the combination out of 
hardware and the CPU's ability to react, save its current status, do 
something and restore the previous status. This value will be pointless 
to you as only the developers of hardware use this information to make 
sure that what they plan is possible.

Erich