Any place where these different clock models is described? And defined (what is tsc?)
Martin Burnicki <[EMAIL PROTECTED]> writes: >Thierry, >Thierry MARTIN wrote: >> Hello, >> >> Can anyone tell me if a time shift greater than 2s per day is ""normal"" >> on a linux system that has no "external" synchronisation (ntp)? >> >> I tryied "adjtimex -a" which gives unreliable results: it worked fine on >> one machine (less than 1s shift / day) and badly on another one >> (several seconds shift / day) >> >> Any info about this subject would help me. >Which kernel version are you running? Starting with ~2.6.22 a new clock >model has made its way into the Linux kernel. There are different modules >which can use different hardware timers for timekeeping, and there seem to >be some problems with certain modules on certain hardware (i.e. chipsets on >the motherboard). >To list available clock sources under kernel ~2.6.22 or newer: ># cat /sys/devices/system/clocksource/clocksource0/available_clocksource >hpet acpi_pm pit jiffies tsc >Check which clocksource is currently being used: ># cat /sys/devices/system/clocksource/clocksource0/current_clocksource >tsc >Change the clock source: ># echo tsc > \ >/sys/devices/system/clocksource/clocksource0/current_clocksource >For a test it is also possible to override the default clock source using a >boot parameter, e.g.: >clocksource=jiffies >You may want to try if some other of the available modules does a better job >in timekeeping. If the active module doesn't work correctly then the >frequency drift often exceeds the maximum drift ntpd can handle. >Martin >-- >Martin Burnicki >Meinberg Funkuhren >Bad Pyrmont >Germany _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
