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

[Namhyung Kim]

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@xxxxxxxxxx>
---
 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