On Sunday, April 6, 2008 at 19:36:40 +0000, Unruh wrote: > Serge Bets <[EMAIL PROTECTED]> writes: >> The eleven-minutes write takes some tens of microseconds; normal >> hwclock some tens of milliseconds; hwclock --nointerrupt some plain >> seconds. > To write the rtc properly takes at least a second.
I was talking about processor time consumed. As for wall clock time elapsed, indeed a background cron job mostly sleeping or waiting for an interrupt during one or two seconds is rather harmless. > In the case the machine comes up again in a few seconds, the rate > correction is irrelevant anyway. Drift compensation is important even for a stop and go: maybe the stop was a crash, and the RTC was last written hours ago. But the point was more that as long as the downtime stays short, the temperature of the RTC, and thus its instant drift rate, does not vary too much from the mean runtime values. Therefore it makes sense to pick the runtime rate for compensation. Only in this specific 24/7 case. > And if the system reads the clock badly it will be out by about a > second anyway. This never happens on a proper setup: hwclock --hctosys syncs on the RTC down to a few microseconds. Serge. -- Serge point Bets arobase laposte point net _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
