On Tue, 2009-06-02 at 18:22 +0200, Miroslav Lichvar wrote: > On Tue, Jun 02, 2009 at 02:20:39AM +0200, Ingo Molnar wrote: > > > > Not just that - but there's calibration noise during bootup that can > > cause randomly distributed recalibrations as well. So other hosts in > > a mixed environment will see inconsistencies anyway, after every > > bootup. [snip] > As for the calibration issue, would it be possible to export the > information that an instable clocksource is used and when was the last > time it was calibrated? Then we'd know when the drift file should not > be trusted and let NTP calculate the frequency directly (it takes > about 15 minutes). Just to de-thread the issues here, the calibration noise issue really is separate from the SHIFT_PLL convergence issue. I'd really prefer the calibration noise issue to be resolved by the kernel, as its really only an issue on a subset of x86 machines. The tsc_khz= boot option I proposed earlier for folks who really care seems to me like a good route. The only NTPd side change to help the calibration issue that might be useful, would be a explicit ntp option to force NTP to always calculate the freq on startup if the drift file was present or not. Anything else would be way too much of a hack to get around bad kernel behavior. thanks -john -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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