New "timeout" api, to replace callout

Poul-Henning Kamp phk at
Sun Dec 2 07:08:44 PST 2007

In message <20071202055031.A8107 at>, Luigi Rizzo writes:

>This is why i suggest having a 'scale' that can represent '1 tick'
>(and also don't depend on TIMEOUT_MSEC == 1000 and so on, but keep
>them opaque and require that the client code uses one of the supported

Using a deadline timer based in the HPET, the timeout can be scheduled
to any 1/14318181th of a second and there will be no concept of "a
tick" as we know it now.

Clients should say how often they want to be called, and they should
express it in terms of time, not based on some implementation detail
of a historical implementation of the scheduler.

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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