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Date: Mon, 24 Jul 2006 13:40:45 -0600
From: Scott Long <scottl@samsco.org>
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To: Marcelo Gardini do Amaral <marcelo@registro.br>
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Cc: Peter Jeremy <peterjeremy@optushome.com.au>, freebsd-stable@freebsd.org,
	Ed Maste <emaste@phaedrus.sandvine.ca>
Subject: Re: How to setup polling on 'bge' interface
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Marcelo Gardini do Amaral wrote:
>>>The limited testing I've done on a Sun V20z at work suggests that you
>>>can get better routing throughput in interrupt mode than polling mode.
>>>YMMV and this is before tweaking the polling parameters.  (My testing
>>>also suggests that I don't really need to do any tweaking because
>>>the limiting factor is the gigabit interfaces rather than the V20z).
> 
> 
> I've noticed a higher (and variable) RTT with polling mode activated,
> without tweaking any parameters.
> 

Yes, the RTT will vary based on whether the interface has to wait a full
tick or only a partial tick for the polling loop to become active. 
Adaptive polling eliminates most of this variance.

Scott