Do I need root (admin) permissions to run userspace 'perf' tool? (perf events are enabled in Linux kernel)

Question

Do I need to have to run perf userspace tool as system administrator (root), or can I run it (or at least some subcommands) as an ordinary user?

Unix programs that can't do what they need to do for lack of permissions will usually thrown an error if they can't do their job. Run it and see!
I am asking this question to decide whether it is worth trying to install (as ordinary user, in $HOME) userspace part of perf tool (which is/can be non-trivial).
FYI in Ubuntu perf is in linux-tools package, so installing perf there is simple.

Gilles · Accepted Answer · 2011-06-02 17:12:58Z

What you can do with perf without being root depends on the kernel.perf_event_paranoid sysctl setting.

kernel.perf_event_paranoid = 2: you can't take any measurements. The perf utility might still be useful to analyse existing records with perf ls, perf report, perf timechart or perf trace.
kernel.perf_event_paranoid = 1: you can trace a command with perf stat or perf record, and get kernel profiling data.
kernel.perf_event_paranoid = 0: you can trace a command with perf stat or perf record, and get CPU event data.
kernel.perf_event_paranoid = -1: you get raw access to kernel tracepoints (specifically, you can mmap the file created by perf_event_open, I don't know what the implications are).

Nice. cat /proc/sys/kernel/perf_event_paranoid returns 1, so it seems that I would be able to take at least some measurements (BTW. whats the difference betwen "kernel profiling data" and "CPU event data"? Reference is enough)
@Jakub: From what I understand, kernel events let you see calls to various kernel functions. CPU events are counters in the CPU that tell you how many times a particular location in memory was hit. I've never used them, so I can't tell you more about them; LWN has quite a few article on the topic, and it's still evolving.

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