Evaluation of High Precision Event Timer Driver for userland timer facility

Poul-Henning Kamp phk at phk.freebsd.dk
Tue Jun 19 10:45:51 UTC 2007

In message <46769FB3.8060002 at ybb.ne.jp>, Takeharu KATO writes:

>> Basing this facility on the HPET almost guarantees that we cannot
>> use it in FreeBSD, because the HPET is not available on more than
>> a couple of our architectures.
>Certainly the facility is not available non-PC platform, it
>highly depends on board specs.
>How do you think about introducing this facility as a kernel option.
>As far as I think, this facility is a kind of device driver, this is 
>not timer facility which is used in common.

I would prefer if the API seen from the rest of the kernel did not
change depending on if you have something like this or not.  That
requires changes to the current tsleep(9) API, but we have already
been talking about that for some time (Search the arch@ list)

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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