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>
ba3dec99fc