Performance counters may be unavailable due to various reasons (such as
access restriction via sysctl properties or the CPU model being unknown
to libpfm). On the other hand, for debugging llvm-exegesis itself it is
still useful to be able to run generated code snippets to ensure that
the snippet does not crash at run time.
The --use-dummy-perf-counters command line option makes llvm-exegesis
behave just as usual except for using fake event counts instead of asking
the kernel for actual values.
~~
Huawei RRI, OS Lab
I think you can add something about not using actual perf counters if that's waht the user wants:
"If you are debugging and you don't want to actually read performance counters, use --use-dummy-perf-events