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)