perf parse: Report initial event parsing error

Record the first event parsing error and report. Implementing feedback
from Jiri Olsa:

  https://lkml.org/lkml/2019/10/28/680

An example error is:

  $ tools/perf/perf stat -e c/c/
  WARNING: multiple event parsing errors
  event syntax error: 'c/c/'
                         \___ unknown term

  valid terms: event,filter_rem,filter_opc0,edge,filter_isoc,filter_tid,filter_loc,filter_nc,inv,umask,filter_opc1,tid_en,thresh,filter_all_op,filter_not_nm,filter_state,filter_nm,config,config1,config2,name,period,percore

Initial error:

  event syntax error: 'c/c/'
                      \___ Cannot find PMU `c'. Missing kernel support?
  Run 'perf list' for a list of valid events

   Usage: perf stat [<options>] [<command>]

      -e, --event <event>   event selector. use 'perf list' to list available events

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Allison Randal <allison@lohutok.net>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Anju T Sudhakar <anju@linux.vnet.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@linux.ibm.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: http://lore.kernel.org/lkml/20191116074652.9960-1-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/tools/perf/arch/powerpc/util/kvm-stat.c b/tools/perf/arch/powerpc/util/kvm-stat.c
index 9cc1c4a9dec4..16807269317c 100644
--- a/tools/perf/arch/powerpc/util/kvm-stat.c
+++ b/tools/perf/arch/powerpc/util/kvm-stat.c
@@ -113,10 +113,10 @@ static int is_tracepoint_available(const char *str, struct evlist *evlist)
 	struct parse_events_error err;
 	int ret;
 
-	err.str = NULL;
+	bzero(&err, sizeof(err));
 	ret = parse_events(evlist, str, &err);
 	if (err.str)
-		pr_err("%s : %s\n", str, err.str);
+		parse_events_print_error(&err, "tracepoint");
 	return ret;
 }