perf tools: Force uncore events to system wide monitoring
Make system wide (-a) the default option if no target was specified and
one of following conditions is met:
- there's no workload specified (current behaviour)
- there is workload specified but all requested
events are system wide ones
Mixed events core/uncore with workload:
$ perf stat -e 'uncore_cbox_0/clockticks/,cycles' sleep 1
Performance counter stats for 'sleep 1':
<not supported> uncore_cbox_0/clockticks/
980,489 cycles
1.
000897406 seconds time elapsed
Uncore event with workload:
$ perf stat -e 'uncore_cbox_0/clockticks/' sleep 1
Performance counter stats for 'system wide':
281,473,897,192,670 uncore_cbox_0/clockticks/
1.
000833784 seconds time elapsed
Committer note:
When testing I realized the default case for !root, i.e. no events
passed via -e, was broke by v2 of this patch, reported and after a
patch provided by Jiri it is back working:
[acme@jouet linux]$ perf stat usleep 1
Performance counter stats for 'usleep 1':
0.401335 task-clock:u (msec) # 0.297 CPUs utilized
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
48 page-faults:u # 0.120 M/sec
458,146 cycles:u # 1.142 GHz
245,113 instructions:u # 0.54 insn per cycle
47,991 branches:u # 119.578 M/sec
4,022 branch-misses:u # 8.38% of all branches
0.
001350029 seconds time elapsed
[acme@jouet linux]$
Suggested-and-Tested-by: Borislav Petkov <bp@alien8.de>
Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/20170227094818.GA12764@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
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