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Will rr work on my system
Simon Sobisch edited this page Apr 26, 2022
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This question mostly pertains to Virtual Machines rather than real hardware. To check if it's supposed to work execute the following
$ perf stat -e br_inst_retired.conditional true
Performance counter stats for 'true':
95,027 br_inst_retired.conditional
0.003255114 seconds time elapsed
0.003127000 seconds user
0.000000000 seconds sys
Check that br_inst_retired.conditional
value is not zero in the output.
On newer systems you might get an error that says that there is an event syntax error and that br_inst_retired.conditional
does not exist. If that occurs, try:
$ perf stat -e br_inst_retired.cond true
$ perf stat -e ex_ret_cond true
Performance counter stats for 'true':
17.525 ex_ret_cond:u
0,002422402 seconds time elapsed
0,002737000 seconds user
0,000000000 seconds sys
Check that ex_ret_cond:u
value is not zero in the output.
You will also likely have to change your kernel.perf_event_paranoid
setting to 1, at least when recording.
That is documented on the Building-And-Installing page.