5.15 kernel needs at least backporting the following patch to make the perf
working as expected:
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/drivers/perf/arm_pmu.c?id=5c816728651ae425954542fed64d21d40cb75a9f
$ sudo taskset -c 7 ./perf stat -e armv8_cortex_a55/cpu_cycles/ -e
armv8_cortex_a78/cpu_
cycles/ -e cycles sleep 5
Performance counter stats for 'sleep 5':
<not counted> armv8_cortex_a55/cpu_cycles/
(0.00%)
1451459 armv8_cortex_a78/cpu_cycles/
<not counted> cycles
(0.00%)
5.001872700 seconds time elapsed
0.001533000 seconds user
0.000000000 seconds sys
$ sudo taskset -c 0 ./perf stat -e armv8_cortex_a55/cpu_cycles/ -e
armv8_cortex_a78/cpu_
cycles/ -e cycles sleep 5
Performance counter stats for 'sleep 5':
3089794 armv8_cortex_a55/cpu_cycles/
<not counted> armv8_cortex_a78/cpu_cycles/
(0.00%)
3089794 cycles
5.005167986 seconds time elapsed
0.000000000 seconds user
0.004539000 seconds sys
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https://bugs.launchpad.net/bugs/2060063
Title:
PMU counters for Cortex-A78 not working correctly
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