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To: Andre Oppermann <andre@freebsd.org>
Subject: Re: polling's future [was: Re: Dynamic Ticks/HZ]
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From: "Poul-Henning Kamp" <phk@phk.freebsd.dk>
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Date: Tue, 06 Nov 2012 10:46:28 +0000
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Cc: Davide Italiano <davide@freebsd.org>, Ryan Stone <rysto32@gmail.com>,
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--------
In message <5098E8B4.5040309@freebsd.org>, Andre Oppermann writes:

>> I think it should go away, and if there still is a relevant
>> usage segment, be replaced by _real_ "device-polling" which is
>> not tied to the network stack.
>
>Don't we already have the equivalent with a fast interrupt thread
>that simply acknowledges and disables the interrupt [...]

The point is that not all hardware have interrupt-pacing, so
being able to poll at a lower rate in software would save overhead.

I'm not sure if the hardware where this applies is still relevant,
it would probably be mostly in the embedded space.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk@FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.