On 16/09/18 14:15, Sean Austin Critica wrote: > > > Can I directly observe these sources and see which ones are stable > (maybe by dumping them periodically, remotely from a machine with a > known stable clock)? The OS in this case is RedHat EL 7. > > >
"Directly observe": no. But you can look at the kernel log to see which clock source the OS has selected: # dmesg | grep clocksource [ 0.000000] clocksource: refined-jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645519600211568 ns [ 0.000000] clocksource: hpet: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 79635855245 ns [ 0.053021] clocksource: jiffies: mask: 0xffffffff max_cycles: 0xffffffff, max_idle_ns: 7645041785100000 ns [ 0.181027] clocksource: Switched to clocksource hpet [ 0.198695] clocksource: acpi_pm: mask: 0xffffff max_cycles: 0xffffff, max_idle_ns: 2085701024 ns [ 0.906180] clocksource: tsc: mask: 0xffffffffffffffff max_cycles: 0x2879c5f06f2, max_idle_ns: 440795220049 ns [ 1.931401] clocksource: Switched to clocksource tsc You can then look in your CPU's manual to determine whether the selected clocksource is influenced by SpeedStep (or whatever dynamic CPU speed changes are called these days). HTH, Jan _______________________________________________ questions mailing list questions@lists.ntp.org http://lists.ntp.org/listinfo/questions
