Messages in this thread | | | Date | Sat, 28 May 2022 16:01:57 +0200 | From | Peter Zijlstra <> | Subject | Re: [PATCH v2] perf metrics: Add literal for system TSC frequency |
| |
On Fri, May 27, 2022 at 07:54:19AM -0700, Andi Kleen wrote:
> > This all seems bonghits inspired... and perf actually does expose the > > tsc frequency. What do you think is in perf_event_mmap_page::time_* ? > > > That's not really available to perf stat, which is the primary metrics user.
Why not? You can mmap any perf-fd (even software events) and these fields should be filled out.
It should work on any x86 CPU that has a TSC. The only caveat is that the kernel must not have marked the TSC unstable.
It could even work for virt -- all you need is for virt to use native_sched_clock() instead of the paravirt nonsense.
| |