Commits
Len Brown committed ba3dec99fc9
tools/power turbostat: Gracefully handle ACPI S3
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>