Re: [RFC PATCH V2 4/9] perf/x86: Enable post-processing monotonic raw conversion

[Thomas Gleixner]

Kan!

On Mon, Feb 13 2023 at 11:07, kan liang wrote:
> From: Kan Liang <kan.liang@xxxxxxxxxxxxxxx>
> +	} else if (perf_event_hw_time(event)) {
> +		struct ktime_conv mono;
> +
> +		userpg->cap_user_time_mono_raw = 1;
> +		ktime_get_fast_mono_raw_conv(&mono);

What guarantees that the clocksource used by the timekeeping core is
actually TSC? Nothing at all. You cannot make assumptions here.

Thanks,

        tglx