linux-kernel - [PATCH] perf stat: Failure with "Operation not supported"

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Date:	Fri, 2 Dec 2011 09:38:33 +1100
From:	Anton Blanchard <anton@...ba.org>
To:	David Ahern <dsahern@...il.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Arnaldo Carvalho de Melo <acme@...hat.com>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Ingo Molnar <mingo@...e.hu>, Paul Mackerras <paulus@...ba.org>
Cc:	linux-kernel@...r.kernel.org
Subject: [PATCH] perf stat: Failure with "Operation not supported"


perf stat is failing on PowerPC:


# perf stat /bin/true
  Error: open_counter returned with 95 (Operation not supported). /bin/dmesg may provide additional information.

  Fatal: Not all events could be opened.


commit 370faf1dd046 (perf stat: Fail softly on unsupported events)
added a check for failure returning ENOENT, but the POWER backend
returns EOPNOTSUPP. It looks like alpha, blackfin and mips do the
same.

With the patch applied, things work as expected:


# perf stat /bin/true
 Performance counter stats for '/bin/true':

          0.362176 task-clock                #    0.623 CPUs utilized          
                 0 context-switches          #    0.000 M/sec                  
                 0 CPU-migrations            #    0.000 M/sec                  
                28 page-faults               #    0.077 M/sec                  
         1,677,020 cycles                    #    4.630 GHz                    
   <not supported> stalled-cycles-frontend 
   <not supported> stalled-cycles-backend  
           431,220 instructions              #    0.26  insns per cycle        
           101,889 branches                  #  281.325 M/sec                  
             4,145 branch-misses             #    4.07% of all branches        

       0.000581361 seconds time elapsed


Signed-off-by: Anton Blanchard <anton@...ba.org>
Cc: <stable@...nel.org> # 3.0+
---

Index: linux/tools/perf/builtin-stat.c
===================================================================
--- linux.orig/tools/perf/builtin-stat.c	2011-12-02 09:09:17.993942921 +1100
+++ linux/tools/perf/builtin-stat.c	2011-12-02 09:10:15.978939340 +1100
@@ -463,7 +463,8 @@ static int run_perf_stat(int argc __used
 
 	list_for_each_entry(counter, &evsel_list->entries, node) {
 		if (create_perf_stat_counter(counter, first) < 0) {
-			if (errno == EINVAL || errno == ENOSYS || errno == ENOENT) {
+			if (errno == EINVAL || errno == ENOSYS ||
+			    errno == ENOENT || errno == EOPNOTSUPP) {
 				if (verbose)
 					ui__warning("%s event is not supported by the kernel.\n",
 						    event_name(counter));
--
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