[RFC 2/2] perf tools: Add 'cgroup-switches' software event

Namhyung Kim
2020-12-02T15:03:16Z

It counts how often cgroups are changed actually during the context
switches.

# perf stat -a -e context-switches,cgroup-switches -a sleep 1

Performance counter stats for 'system wide':

11,267 context-switches
10,950 cgroup-switches

1.015634369 seconds time elapsed

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
---
tools/include/uapi/linux/perf_event.h | 1 +
tools/perf/util/parse-events.c | 4 ++++
tools/perf/util/parse-events.l | 1 +
3 files changed, 6 insertions(+)

diff --git a/tools/include/uapi/linux/perf_event.h b/tools/include/uapi/linux/perf_event.h
index b95d3c485d27..16559703c49c 100644
--- a/tools/include/uapi/linux/perf_event.h
+++ b/tools/include/uapi/linux/perf_event.h
@@ -112,6 +112,7 @@ enum perf_sw_ids {
PERF_COUNT_SW_EMULATION_FAULTS = 8,
PERF_COUNT_SW_DUMMY = 9,
PERF_COUNT_SW_BPF_OUTPUT = 10,
+ PERF_COUNT_SW_CGROUP_SWITCHES = 11,

PERF_COUNT_SW_MAX, /* non-ABI */
};
diff --git a/tools/perf/util/parse-events.c b/tools/perf/util/parse-events.c
index 3b273580fb84..f6a5a099e143 100644
--- a/tools/perf/util/parse-events.c
+++ b/tools/perf/util/parse-events.c
@@ -145,6 +145,10 @@ struct event_symbol event_symbols_sw[PERF_COUNT_SW_MAX] = {
.symbol = "bpf-output",
.alias = "",
},
+ [PERF_COUNT_SW_CGROUP_SWITCHES] = {
+ .symbol = "cgroup-switches",
+ .alias = "",
+ },
};

#define __PERF_EVENT_FIELD(config, name) \
diff --git a/tools/perf/util/parse-events.l b/tools/perf/util/parse-events.l
index 9db5097317f4..88f203bb6fab 100644
--- a/tools/perf/util/parse-events.l
+++ b/tools/perf/util/parse-events.l
@@ -347,6 +347,7 @@ emulation-faults { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_EM
dummy { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_DUMMY); }
duration_time { return tool(yyscanner, PERF_TOOL_DURATION_TIME); }
bpf-output { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_BPF_OUTPUT); }
+cgroup-switches { return sym(yyscanner, PERF_TYPE_SOFTWARE, PERF_COUNT_SW_CGROUP_SWITCHES); }

/*
* We have to handle the kernel PMU event cycles-ct/cycles-t/mem-loads/mem-stores separately.
--
2.29.2.454.gaff20da3a2-goog