perf pmu: Improve error messages for missing PMUs

When a PMU is missing print a better error message mentioning
the missing PMU.

% mkdir empty
% mount --bind empty /sys/devices/msr
% perf stat -M Summary true
event syntax error: '{inst_retired.any,cycles}:W,{cpu_clk_unhalted.thread}:W,{inst_retired.any}:W,{cpu_clk_unhalted.ref_tsc,msr/tsc/}:W,{fp_comp_ops_exe.sse_scalar..'
                     \___ Cannot find PMU `msr'. Missing kernel support?

It still cannot find the right column for aliases, but it's already a vast improvement.

v2: Check asprintf

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: http://lkml.kernel.org/r/20170913215006.32222-1-andi@firstfloor.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

3 files changed, 16 insertions, 7 deletions

diff --git a/tools/perf/util/metricgroup.c b/tools/perf/util/metricgroup.c
index 2d60114f1870..fa37ef79517a 100644
--- a/tools/perf/util/metricgroup.c
+++ b/tools/perf/util/metricgroup.c
@@ -477,7 +477,7 @@ int metricgroup__parse_groups(const struct option *opt,
         memset(&parse_error, 0, sizeof(struct parse_events_error));
         ret = parse_events(perf_evlist, extra_events.buf, &parse_error);
         if (ret) {
-                pr_err("Cannot set up events %s\n", extra_events.buf);
+                parse_events_print_error(&parse_error, extra_events.buf);
                 goto out;
         }
         strbuf_release(&extra_events);
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 75588920fccc..9183913a6174 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -1219,11 +1219,17 @@ static int __parse_events_add_pmu(struct parse_events_state *parse_state,
         struct perf_pmu_info info;
         struct perf_pmu *pmu;
         struct perf_evsel *evsel;
+        struct parse_events_error *err = parse_state->error;
         LIST_HEAD(config_terms);
 
         pmu = perf_pmu__find(name);
-        if (!pmu)
+        if (!pmu) {
+                if (asprintf(&err->str,
+                                "Cannot find PMU `%s'. Missing kernel support?",
+                                name) < 0)
+                        err->str = NULL;
                 return -EINVAL;
+        }
 
         if (pmu->default_config) {
                 memcpy(&attr, pmu->default_config,
@@ -1733,8 +1739,8 @@ static int get_term_width(void)
         return ws.ws_col > MAX_WIDTH ? MAX_WIDTH : ws.ws_col;
 }
 
-static void parse_events_print_error(struct parse_events_error *err,
-                                     const char *event)
+void parse_events_print_error(struct parse_events_error *err,
+                              const char *event)
 {
         const char *str = "invalid or unsupported event: ";
         char _buf[MAX_WIDTH];
@@ -1789,8 +1795,6 @@ static void parse_events_print_error(struct parse_events_error *err,
                 zfree(&err->str);
                 zfree(&err->help);
         }
-
-        fprintf(stderr, "Run 'perf list' for a list of valid events\n");
 }
 
 #undef MAX_WIDTH
@@ -1802,8 +1806,10 @@ int parse_events_option(const struct option *opt, const char *str,
         struct parse_events_error err = { .idx = 0, };
         int ret = parse_events(evlist, str, &err);
 
-        if (ret)
+        if (ret) {
                 parse_events_print_error(&err, str);
+                fprintf(stderr, "Run 'perf list' for a list of valid events\n");
+        }
 
         return ret;
 }
diff --git a/tools/perf/util/parse-events.h b/tools/perf/util/parse-events.h
index 635135125111..3909ca0639f2 100644
--- a/tools/perf/util/parse-events.h
+++ b/tools/perf/util/parse-events.h
@@ -202,6 +202,9 @@ int is_valid_tracepoint(const char *event_string);
 int valid_event_mount(const char *eventfs);
 char *parse_events_formats_error_string(char *additional_terms);
 
+void parse_events_print_error(struct parse_events_error *err,
+                              const char *event);
+
 #ifdef HAVE_LIBELF_SUPPORT
 /*
  * If the probe point starts with '%',