Folks,
I am trying to run linux 'perf' on a new board with 2 ARM cortex-a9 CPUs. After compiling the kernel to include perf tool, i run 'perf stat true' and it returns valid stats. But when I run 'perf record' to profile my program, it doesn't record any samples. Also, running the following command gives me an error.
# perf record -e cycles:u,cycles:k,instructions:u,instructions:k -p 1 Error:PMU Hardware doesn't support sampling/overflow-interrupts.
This makes me suspect that PMU is not initialized. Can someone suggest me how to go about this issue?
# perf stat true Performance counter stats for 'true': 1.101860 task-clock (msec) # 0.523 CPUs utilized 0 context-switches # 0.000 K/sec 0 cpu-migrations # 0.000 K/sec 22 page-faults # 0.020 M/sec 1094830 cycles # 0.994 GHz 314416 instructions # 0.29 insn per cycle 29305 branches # 26.596 M/sec 16522 branch-misses # 56.38% of all branches 0.002106000 seconds time elapsed
I have enabled almost all the kernel configs I could think of related to PMU and Profilign.
One question though: While browsing the forum here, I found this thread "How to configure Cortex-A57 PMU". Can you please tell me what does it mean by configuring the PMU? Do I also need to perform the similar steps?