Re: [PATCH] perf/x86/intel/ds: Fix the conversion from TSC to perf time

[Peter Zijlstra]

On Mon, Jan 23, 2023 at 09:20:27AM -0800, kan.liang@xxxxxxxxxxxxxxx wrote:
> The TSC unstable case seems to be some corner cases (e.g., due to broken
> BIOS). This patch doesn't support the conversion when the TSC is
> unstable. The TSC in a PEBS record will be dropped and fallback to the
> software perf time provided by the generic code.

:-(

You're saying there's modern systems (PEBS timestamps are fairly new)
that trigger unstable TSC ?

What systems in specific have you observed this on -- we really need to
name and shame them, this is fully unacceptable.