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Date: Fri, 9 Apr 2004 10:55:03 -0700
From: Luigi Rizzo <luigi@freebsd.org>
To: Ruslan Ermilov <ru@freebsd.org>
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	from ru@freebsd.org on Fri, Apr 09, 2004 at 07:47:24PM +0300
cc: net@freebsd.org
Subject: Re: polling(4) and rl(4)
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On Fri, Apr 09, 2004 at 07:47:24PM +0300, Ruslan Ermilov wrote:
> Hey Luigi,
> 
> Have you actually measured the performance of rl(4) with polling(4)
> enabled?  With 8139 anomaly of four (register based) TX descriptors

no, nor i did expect any improvement -- the code was only there
to help when the 8139C+ was supported. But now that happens in
a different driver.

Re. the removal, I still think it is beneficial in receiving,
(not performancewise, just to avoid livelock), so as a temporary
measure why don't you just short-circuit the logic that enables
polling in the driver rather than ripping it out completely ?

cheers
luigi (rushing out for dinner)

> it's becoming a royal pain in the ass with polling(4) enabled --
> the TX performance just sucks -- I could only get the comparable
> results with HZ=5000, which is overheating my CPU.  My suggestion
> is to drop polling(4) support from the rl(4) driver completely.
> 
> Are there any objections?  Has anybody got different results with
> rl(4) and polling(4) enabled?
> 
> Having it in re(4) is of course a good thing.  ;)
> 
> As an aside, I've started working on the ``[-]polling'' option for
> ifconfig(8) that, when done, will allow changing the polling status
> of individual interfaces in run-time, e.g., the following command
> will disable polling on nge0:
> 
> 	ifconfig nge0 -polling
> 
> 
> Cheers,
> -- 
> Ruslan Ermilov
> ru@FreeBSD.org
> FreeBSD committer