[PATCH 30/35] perf tools: Force uncore events to system wide monitoring

From: Arnaldo Carvalho de Melo
Date: Mon Mar 06 2017 - 14:44:00 EST


From: Jiri Olsa <jolsa@xxxxxxxxxx>

Make system wide (-a) the default option if no target was specified and
one of following conditions is met:

- there's no workload specified (current behaviour)
- there is workload specified but all requested
events are system wide ones

Mixed events core/uncore with workload:

$ perf stat -e 'uncore_cbox_0/clockticks/,cycles' sleep 1

Performance counter stats for 'sleep 1':

<not supported> uncore_cbox_0/clockticks/
980,489 cycles

1.000897406 seconds time elapsed

Uncore event with workload:

$ perf stat -e 'uncore_cbox_0/clockticks/' sleep 1

Performance counter stats for 'system wide':

281,473,897,192,670 uncore_cbox_0/clockticks/

1.000833784 seconds time elapsed

Committer note:

When testing I realized the default case for !root, i.e. no events
passed via -e, was broke by v2 of this patch, reported and after a
patch provided by Jiri it is back working:

[acme@jouet linux]$ perf stat usleep 1

Performance counter stats for 'usleep 1':

0.401335 task-clock:u (msec) # 0.297 CPUs utilized
0 context-switches:u # 0.000 K/sec
0 cpu-migrations:u # 0.000 K/sec
48 page-faults:u # 0.120 M/sec
458,146 cycles:u # 1.142 GHz
245,113 instructions:u # 0.54 insn per cycle
47,991 branches:u # 119.578 M/sec
4,022 branch-misses:u # 8.38% of all branches

0.001350029 seconds time elapsed

[acme@jouet linux]$

Suggested-and-Tested-by: Borislav Petkov <bp@xxxxxxxxx>
Signed-off-by: Jiri Olsa <jolsa@xxxxxxxxxx>
Tested-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Adrian Hunter <adrian.hunter@xxxxxxxxx>
Cc: David Ahern <dsahern@xxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Link: http://lkml.kernel.org/r/20170227094818.GA12764@krava
Signed-off-by: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
---
tools/perf/builtin-stat.c | 33 ++++++++++++++++++++++++++++++---
tools/perf/util/parse-events.c | 5 +++--
2 files changed, 33 insertions(+), 5 deletions(-)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index f4f555a67e9b..f53f449d864d 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -2350,6 +2350,35 @@ static int __cmd_report(int argc, const char **argv)
return 0;
}

+static void setup_system_wide(int forks)
+{
+ /*
+ * Make system wide (-a) the default target if
+ * no target was specified and one of following
+ * conditions is met:
+ *
+ * - there's no workload specified
+ * - there is workload specified but all requested
+ * events are system wide events
+ */
+ if (!target__none(&target))
+ return;
+
+ if (!forks)
+ target.system_wide = true;
+ else {
+ struct perf_evsel *counter;
+
+ evlist__for_each_entry(evsel_list, counter) {
+ if (!counter->system_wide)
+ return;
+ }
+
+ if (evsel_list->nr_entries)
+ target.system_wide = true;
+ }
+}
+
int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
{
const char * const stat_usage[] = {
@@ -2456,9 +2485,7 @@ int cmd_stat(int argc, const char **argv, const char *prefix __maybe_unused)
} else if (big_num_opt == 0) /* User passed --no-big-num */
big_num = false;

- /* Make system wide (-a) the default target. */
- if (!argc && target__none(&target))
- target.system_wide = true;
+ setup_system_wide(argc);

if (run_count < 0) {
pr_err("Run count must be a positive number\n");
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 67a8aebc67ab..54355d3caf09 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -316,8 +316,9 @@ __add_event(struct list_head *list, int *idx,
return NULL;

(*idx)++;
- evsel->cpus = cpu_map__get(cpus);
- evsel->own_cpus = cpu_map__get(cpus);
+ evsel->cpus = cpu_map__get(cpus);
+ evsel->own_cpus = cpu_map__get(cpus);
+ evsel->system_wide = !!cpus;

if (name)
evsel->name = strdup(name);
--
2.9.3