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[LUG] Jiffies and the perils of not properly solving a problem properly

 

In September 2010 I asked here when "jiffies" are available as a
clocksource in Linux.

Same question - but now I need the answer as the evil workaround started
failing.

In particular this is a XEN HVM guest.
The only available clocksource currently is acpi_pm and this is not stable.

So I think I need a new kernel or settings that get me "jiffies" as a
clock source but I can't find any useful explanation of when "jiffies"
is available as a clock source or even if it is listed in
"available_clocksource" when it is available, or whether I need to
append kernel options to get it listed.

None of my systems list "jiffies" or other free running clock source.
Most list "tsc hpet acpi_pm", some only "acpi_pm" but then they are all
Debian so it is unsurprising they are fairly uniform.

So when is it listed?

Even if you don't know please feel free to send me the output of these
commands (offlist?) for me to discover if there is a pattern:

$ uname -a
$ cat /sys/devices/system/clocksource/clocksource/available_clocksource


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