On some systems, using Perf hardware counters can be restricted by the value of /proc/sys/kernel/perf_event_paranoid.
| perf_event_paranoid | Description |
|---|---|
| 3 | Disable use of Perf events |
| 2 | Allow only user-space measurements |
| 1 | Allow kernel and user-space measurements |
| 0 | Allow access to CPU-specific data, but not raw trace‐point samples. |
| -1 | No restrictions |
The value of /proc/sys/kernel/perf_event_paranoid must be 2 or lower to collect Perf metrics. To set this until the next reboot, run the following commands:
sudo sysctl -w kernel.perf_event_paranoid=2
To permanently set the paranoid level, add the following line to /etc/sysctl.conf:
kernel.perf_event_paranoid=2