[ntp:questions] Linux 11-minute mode (RTC update)

Serge Bets serge.bets at NOSPAM.laposte.invalid
Fri Jul 25 13:08:21 UTC 2008

 On Thursday, July 24, 2008 at 18:51:03 +0000, Unruh wrote:

> Three orders. (avg 8ms vs about 20usec) but yes, that is pretty
> terrible.

How do you count 20 µs of average error in timestamping an RTC update
interrupt? This seems quite high to me. A quick statistical check here
gave me 3.3 µs on my old and slow machine, and I naively imagined that
a modern machine like yours can only do better.

> Reading the HPET spec and the hpet.c code in the kernel it would seem
> to me that you could disable the legacy behaviour while keeping the
> hpet for high speed timing/cpu clock/tickless operation.

Then HPET and RTC would probably both work fine. However those who know
seem to say that this would be very difficult or impossible to do
uniformly on all concerned motherboards. :-(

Serge point Bets arobase laposte point net

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