polling's future [was: Re: Dynamic Ticks/HZ]

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Nov 6 10:46:30 UTC 2012

In message <5098E8B4.5040309 at 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 at 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.

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