In message <[EMAIL PROTECTED]>, "M. Warner Losh" writes: >In message: <[EMAIL PROTECTED]> > Markus Kuhn <[EMAIL PROTECTED]> writes: >: "M. Warner Losh" wrote on 2006-01-19 19:20 UTC: >: > Effectively, you'd have to have two time scales in the kernel. UTC >: > and UTC-SLS. You make it sound simple, but the hair in doing this may >: > be quite difficult. There's more book for the kernel to keep, and it >: > would have to expose the bookkeeping to userland for ntp to work. >: > What makes this hard is that ntpd may introduce steers into the normal >: > system time at normal times which it doesn't want to confuse with the >: > steers in frequency that are used during a UTC-SLS operation. >: >: You correctly point out some of the design considerations that have to >: go into such code. You describe roughly one of the (several) different >: ways of implementing all this that I have in mind. In comparison to how >: complicated the Mills kernel PLL is already today, that does not >: actually sound like an overwhelming additional complexity. Actually, it >: sounds quite doable when you think through it a bit. Not trivial, but >: carefully doable without performance penalty. > >Anything that makes the Mills' kernel PLL more complicated is unlikely >to be implemented correctly.
Actually the Mills PLL isn't implemented correctly in the first place, The fact that the design is pretty baroque doesn't help. -- Poul-Henning Kamp | UNIX since Zilog Zeus 3.20 [EMAIL PROTECTED] | TCP/IP since RFC 956 FreeBSD committer | BSD since 4.3-tahoe Never attribute to malice what can adequately be explained by incompetence.
