On Thu, Mar 02, 2017 at 08:44:10AM +0100, Jiri Olsa wrote:
> On Wed, Mar 01, 2017 at 06:36:39PM -0300, Arnaldo Carvalho de Melo wrote:
>
> SNIP
>
> > [acme@jouet linux]$ perf stat usleep 1
> >
> > Performance counter stats for 'usleep 1':
> >
> > 2.022049 task-clock:u (msec) # 0.181 CPUs utilized
> >
> > 0 context-switches:u # 0.000 K/sec
> >
> > 0 cpu-migrations:u # 0.000 K/sec
> >
> > 48 page-faults:u # 0.024 M/sec
> >
> > 2,177,301 cycles:u # 1.077 GHz
> >
> > 245,106 instructions:u # 0.11 insn per cycle
> >
> > 48,000 branches:u # 23.738 M/sec
> >
> > 3,936 branch-misses:u # 8.20% of all
> > branches
> >
> > 0.011181563 seconds time elapsed
> >
> > [acme@jouet linux]$
> >
> > ---------------------------------------------
> >
> > Seems related to the auto :u done when the user can't do kernel profiling,
> > etc.
> >
> > Re-applying your patch, to triple check:
> >
> > [acme@jouet linux]$ perf stat usleep 1 2>&1 | head -2
> > Error:
> > You may not have permission to collect system-wide stats.
> > [acme@jouet linux]$
> >
> > ------------------------------------------------
> >
> > Waiting for v3 :-)
>
> oh my... I'll check
could you please try with attched change
thanks,
jirka
---
diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 1320352cda04..f53f449d864d 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2374,7 +2374,8 @@ static void setup_system_wide(int forks)
return;
}
- target.system_wide = true;
+ if (evsel_list->nr_entries)
+ target.system_wide = true;
}
}
