perf tools: Check maximum frequency rate for record/top
authorJiri Olsa <jolsa@redhat.com>
Tue, 5 Nov 2013 14:14:47 +0000 (15:14 +0100)
committerArnaldo Carvalho de Melo <acme@redhat.com>
Tue, 5 Nov 2013 18:15:08 +0000 (15:15 -0300)
commit714647bdc516330e4405b39677d7f763e016c685
tree13aaae6374601031ff2393d11ee8a28d37072a6d
parenta9862418547e818aa5842840aecfa81d733b97e9
perf tools: Check maximum frequency rate for record/top

Adding the check for maximum allowed frequency rate defined in following
file:

  /proc/sys/kernel/perf_event_max_sample_rate

When we cross the maximum value we fail and display detailed error
message with advise.

  $ perf record -F 3000 ls
  Maximum frequency rate (2000) reached.
  Please use -F freq option with lower value or consider
  tweaking /proc/sys/kernel/perf_event_max_sample_rate.

In case user does not specify the frequency and the default value cross
the maximum, we display warning and set the frequency value to the
current maximum.

  $ perf record ls
  Lowering default frequency rate to 2000.
  Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate.

Same messages are used for 'perf top'.

Signed-off-by: Jiri Olsa <jolsa@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Corey Ashford <cjashfor@linux.vnet.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1383660887-1734-4-git-send-email-jolsa@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
tools/perf/builtin-record.c
tools/perf/builtin-top.c
tools/perf/util/evlist.h
tools/perf/util/record.c