Unable to run `perf stat` on Intel hybrid system with e-core (atom) disabled

[Yuzhong Huang <yuzhongh@usc.edu>]

Hi Linux Perf Users,

On my system (intel 12600k), if I disable the e-cores in bios, perf
stat command would fail:
> root@localhost:~# perf stat sleep 1
> Error:
> The sys_perf_event_open() syscall returned with 12 (Cannot allocate memory) for event (cpu_atom/cycles/).
> /bin/dmesg | grep -i perf may provide additional information.

Looks like it's trying to read some counters from the e-core (atom). I
have tried `perf stat --cputype=core  sleep 1`, still doesn't work.

I notice that if I do a system wide `perf stat`, it works as expected.
Other perf tools like `perf record`, `perf top` all work as expected.

I have run `perf list`, which does include all kinds of events from
e-core(atom), even though they have been disabled in the bios.

I wonder if there is a switch to get around this? For example to
override the list of events. Or if it has to be fixed somewhere in the
code, which file should I look at? I am happy to work on a patch.

Yuzhong Huang
University of Southern California