Event Tracing won't work due to perf_event_paranoid. Any notification?

[DanielTimLee]

Just followed instruction Event Tracing, but /* linux:sched-out */ won't show up on my machine.
And with a verbose message, finally found out the reason.

$ cat /proc/sys/kernel/perf_event_paranoid
3

How about info users with the warning message about setting /proc/sys/kernel/perf_event_paranoid being 2 or smaller to enable Event Tracing?

Example:

WARN: cannot trace event: perf_event_paranoid is greater than 2. 
WARN: To enable, $ echo 2 > /proc/sys/kernel/perf_event_paranoid

(Working on Ubuntu 18.04.1 4.15.0-29-generic)

[namhyung]

But it might be annoying if user don't have the right to change the setting. How about showing it as a debug message rather than a warning?

[DanielTimLee]

Oh. It makes sense. Never thought of it in that way. Might be better to just keep it unchanged. I'll close the issue right away. Namhyung Kim <[email protected]>:

But it might be annoying if user don't have the right to change the setting. How about showing it as a debug message rather than a warning? — You are receiving this because you authored the thread. Reply to this email directly, view it on GitHub <#513 (comment)>, or mute the thread <https://github.com/notifications/unsubscribe-auth/APqSaNIioDFcSSNGH0MUjqg2aPcYeTPxks5ucgn1gaJpZM4WvS26> .

-- Daniel T. Lee [email protected]