1 files changed, 34 insertions, 1 deletions

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 147a27e8c937..30e6b374e095 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -172,6 +172,7 @@ static bool			interval_count;
 static const char               *output_name;
 static int                      output_fd;
 static int                      print_free_counters_hint;
+static int                      print_mixed_hw_group_error;
 
 struct perf_stat {
         bool                     record;
@@ -1126,6 +1127,30 @@ static void abs_printout(int id, int nr, struct perf_evsel *evsel, double avg)
                 fprintf(output, "%s%s", csv_sep, evsel->cgrp->name);
 }
 
+static bool is_mixed_hw_group(struct perf_evsel *counter)
+{
+        struct perf_evlist *evlist = counter->evlist;
+        u32 pmu_type = counter->attr.type;
+        struct perf_evsel *pos;
+
+        if (counter->nr_members < 2)
+                return false;
+
+        evlist__for_each_entry(evlist, pos) {
+                /* software events can be part of any hardware group */
+                if (pos->attr.type == PERF_TYPE_SOFTWARE)
+                        continue;
+                if (pmu_type == PERF_TYPE_SOFTWARE) {
+                        pmu_type = pos->attr.type;
+                        continue;
+                }
+                if (pmu_type != pos->attr.type)
+                        return true;
+        }
+
+        return false;
+}
+
 static void printout(int id, int nr, struct perf_evsel *counter, double uval,
                      char *prefix, u64 run, u64 ena, double noise,
                      struct runtime_stat *st)
@@ -1178,8 +1203,11 @@ static void printout(int id, int nr, struct perf_evsel *counter, double uval,
                         counter->supported ? CNTR_NOT_COUNTED : CNTR_NOT_SUPPORTED,
                         csv_sep);
 
-                if (counter->supported)
+                if (counter->supported) {
                         print_free_counters_hint = 1;
+                        if (is_mixed_hw_group(counter))
+                                print_mixed_hw_group_error = 1;
+                }
 
                 fprintf(stat_config.output, "%-*s%s",
                         csv_output ? 0 : unit_width,
@@ -1757,6 +1785,11 @@ static void print_footer(void)
 "       echo 0 > /proc/sys/kernel/nmi_watchdog\n"
 "       perf stat ...\n"
 "       echo 1 > /proc/sys/kernel/nmi_watchdog\n");
+
+        if (print_mixed_hw_group_error)
+                fprintf(output,
+                        "The events in group usually have to be from "
+                        "the same PMU. Try reorganizing the group.\n");
 }
 
 static void print_counters(struct timespec *ts, int argc, const char **argv)