[tip:perf/urgent] perf stat: Print out hint for mixed PMU group error

[tip-bot for Kan Liang]

Commit-ID:  30060eaed769039c6e523b9d159f2b2858fa8907
Gitweb: https://git.kernel.org/tip/30060eaed769039c6e523b9d159f2b2858fa8907
Author: Kan Liang 
AuthorDate: Tue, 24 Apr 2018 11:20:11 -0700
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Tue, 24 Apr 2018 16:11:59 -0300

perf stat: Print out hint for mixed PMU group error

Perf doesn't support mixed events from different PMUs (except software
event) in a group. For this case, only "" or "" are printed out. There is no hint which guides users to fix
the issue.

Checking the PMU type of events to determine if they are from the same
PMU. There may be false alarm for the checking. E.g. the core PMU has
different PMU type. But it should not happen often.

The false alarm can also be tolerated, because:

- It only happens on error path.
- It just provides a possible solution for the issue.

Signed-off-by: Kan Liang 
Cc: Agustin Vega-Frias 
Cc: Andi Kleen 
Cc: Ganapatrao Kulkarni 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Shaokun Zhang 
Cc: Will Deacon 
Link: 
http://lkml.kernel.org/r/1524594014-79243-2-git-send-email-kan.li...@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/builtin-stat.c | 35 ++-
 1 file changed, 34 insertions(+), 1 deletion(-)

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)

[tip:perf/urgent] perf stat: Print out hint for mixed PMU group error

[tip-bot for Kan Liang]

Commit-ID:  30060eaed769039c6e523b9d159f2b2858fa8907
Gitweb: https://git.kernel.org/tip/30060eaed769039c6e523b9d159f2b2858fa8907
Author: Kan Liang 
AuthorDate: Tue, 24 Apr 2018 11:20:11 -0700
Committer:  Arnaldo Carvalho de Melo 
CommitDate: Tue, 24 Apr 2018 16:11:59 -0300

perf stat: Print out hint for mixed PMU group error

Perf doesn't support mixed events from different PMUs (except software
event) in a group. For this case, only "" or "" are printed out. There is no hint which guides users to fix
the issue.

Checking the PMU type of events to determine if they are from the same
PMU. There may be false alarm for the checking. E.g. the core PMU has
different PMU type. But it should not happen often.

The false alarm can also be tolerated, because:

- It only happens on error path.
- It just provides a possible solution for the issue.

Signed-off-by: Kan Liang 
Cc: Agustin Vega-Frias 
Cc: Andi Kleen 
Cc: Ganapatrao Kulkarni 
Cc: Jin Yao 
Cc: Jiri Olsa 
Cc: Namhyung Kim 
Cc: Peter Zijlstra 
Cc: Shaokun Zhang 
Cc: Will Deacon 
Link: 
http://lkml.kernel.org/r/1524594014-79243-2-git-send-email-kan.li...@linux.intel.com
Signed-off-by: Arnaldo Carvalho de Melo 
---
 tools/perf/builtin-stat.c | 35 ++-
 1 file changed, 34 insertions(+), 1 deletion(-)

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)