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Date: Mon, 5 Nov 2012 08:11:41 -0500
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Subject: Re: Dynamic Ticks/HZ
From: Ryan Stone <rysto32@gmail.com>
To: Joe Holden <lists@rewt.org.uk>
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Cc: Davide Italiano <davide@freebsd.org>, FreeBSD Current <current@freebsd.org>
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On Mon, Nov 5, 2012 at 4:40 AM, Joe Holden <lists@rewt.org.uk> wrote:

> doh, running kernel wasn't as GENERIC as I thought it was, looks like
> device polling not only breaks dynamic ticks but also reduces rx ability
> significantly, exactly 150,000 pps per 1000hz on igb versus 650,000 without
>
> Is this a known issue? (and if device polling isn't as useful as it once
> was, should it be removed?)
>

Device polling on modern multiqueue NICs isn't very useful because you're
limited to a single thread for handling packets.  I have a patch that fixes
this that I've let fall by the wayside.