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Re: Unified tracing buffer
On Tue, 23 Sep 2008, Masami Hiramatsu wrote:
> # cat /sys/devices/system/cpu/cpu0/cpuidle/state3/usage
> 171210
C3 stops the TSC. So depending on how many C3 entries you have on the
different cores, your TSCs will drift apart. Some BIOSes do even a
lousy job trying to fixup the TSCs on exit from C3, which makes things
even worse.
> C1: type[C1] promotion[--] demotion[--] latency[001] usage[00000016] duration[00000000000000000000]
> C2: type[C2] promotion[--] demotion[--] latency[001] usage[00037969] duration[00000000000024288003]
> C3: type[C3] promotion[--] demotion[--] latency[057] usage[00171818] duration[00000000001881257636]
>
> Could these help you?
Yup, explains your TSC observation. Nothing we can do about. Broken by
system design :( Welcome in the wonderful world of Inhell/BIOS/ACPI !
Thanks,
tglx