turbostat gives valid results across suspend to idle, aka freeze,
whether invoked in  interval mode, or in command mode.
Indeed, this can be used to measure suspend to idle:

turbostat echo freeze > /sys/power/state

But this does not work across suspend to ACPI S3, because the
processor counters, including the TSC, are reset on resume.
Further, when turbostat detects a problem, it does't forgive
the hardware, and interval mode will print *'s from there on out.

Instead, upon detecting counters going backwards, simply
reset and start over.

Interval mode across ACPI S3: (observe TSC going backwards)

root@sharkbay:/home/lenb/turbostat-src# ./turbostat -M 0x10
     CPU Avg_MHz   Busy% Bzy_MHz TSC_MHz           MSR 0x010
       -       1    0.06     858    2294  0x0000000000000000
       0       0    0.06     847    2294  0x0000002a254b98ac
       1       1    0.06     878    2294  0x0000002a254efa3a
       2       1    0.07     843    2294  0x0000002a2551df65
       3       0    0.05     863    2294  0x0000002a2553fea2
turbostat: re-initialized with num_cpus 4
     CPU Avg_MHz   Busy% Bzy_MHz TSC_MHz           MSR 0x010
       -       2    0.20     849    2294  0x0000000000000000
       0       2    0.26     856    2294  0x0000000449abb60d
       1       2    0.20     844    2294  0x0000000449b087ec
       2       2    0.21     850    2294  0x0000000449b35d5d
       3       1    0.12     839    2294  0x0000000449b5fd5a
^C

Command mode across ACPI S3:
root@sharkbay:/home/lenb/turbostat-src# ./turbostat -M 0x10 sleep 10
./turbostat: Counter reset detected
14.196299 sec
Signed-off-by: Len Brown <len.brown@intel.com>