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perf stat: Fallback to user only counters when perf_event_paranoid > 1 

After 0161028b7c ("perf/core: Change the default paranoia level to 2")
'perf stat' fails for users without CAP_SYS_ADMIN, so just use
'perf_evsel__fallback()' to have the same behaviour as 'perf record',
i.e. set perf_event_attr.exclude_kernel to 1.

Now:

  [acme@jouet linux]$ perf stat usleep 1

   Performance counter stats for 'usleep 1':

          0.352536      task-clock:u (msec)  #   0.423 CPUs utilized
                 0      context-switches:u   #   0.000 K/sec
                 0      cpu-migrations:u     #   0.000 K/sec
                49      page-faults:u        #   0.139 M/sec
           309,407      cycles:u             #   0.878 GHz
           243,791      instructions:u       #   0.79  insn per cycle
            49,622      branches:u           # 140.757 M/sec
             3,884      branch-misses:u      #   7.83% of all branches

       0.000834174 seconds time elapsed

  [acme@jouet linux]$

Reported-by: Ingo Molnar <mingo@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kees Cook <keescook@chromium.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-b20jmx4dxt5hpaa9t2rroi0o@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
4.6.x^2
Arnaldo Carvalho de Melo 2016-05-12 16:25:18 -03:00
parent 08094828b7
commit 42ef8a78c1
1 changed files with 6 additions and 1 deletions
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7
tools/perf/builtin-stat.c
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@ -528,6 +528,7 @@ static int __run_perf_stat(int argc, const char **argv)
perf_evlist__set_leader(evsel_list);
evlist__for_each(evsel_list, counter) {
try_again:
if (create_perf_stat_counter(counter) < 0) {
/*
* PPC returns ENXIO for HW counters until 2.6.37
@ -544,7 +545,11 @@ static int __run_perf_stat(int argc, const char **argv)
if ((counter->leader != counter) ||
!(counter->leader->nr_members > 1))
continue;
}
} else if (perf_evsel__fallback(counter, errno, msg, sizeof(msg))) {
if (verbose)
ui__warning("%s\n", msg);
goto try_again;
}
perf_evsel__open_strerror(counter, &target,
errno, msg, sizeof(msg));