Re: perf lock record fails

From: David Ahern
Date: Sun Jul 08 2012 - 21:54:03 EST


On 7/6/12 7:06 PM, Namhyung Kim wrote:
Hi, David

On Fri, 06 Jul 2012 11:27:39 -0600, David Ahern wrote:
What config options need to be enabled for 'perf lock record' to work?
I tried a number of custom builds and stock Fedora kernels. I always
get:

$ perf lock record -- sleep 1
invalid or unsupported event: 'lock:lock_acquire'

Though trace_lock_acquire exists, CONFIG_LOCKDEP is set, and ftrace is
enabled.

What am I missing?


Weird. AFAICS lock_acquire and lock_release depend on CONFIG_LOCKDEP,
and lock_acquired and lock_contented depend on CONFIG_LOCK_STAT (I guess
it should be warned/commented somewhere?). Maybe CONFIG_EVENT_TRACING?

CONFIG_EVENT_TRACING is set.

I started a comparison with other tracepoints to see if I can decipher why they show up but none of the trace functions for the lock system do (e.g., lock_acquire), but haven't had much time to spend on it. I was hoping Steve or Frederic could explain it quicker. ;-)

David

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