[PATCH v2 3/3] perf tool: add cgroup identifier entry in perf report

[Hari Bathini]

This patch introduces a cgroup identifier entry field in perf report to
identify or distinguish data of different cgroups. It uses the unique
inode number of cgroup namespace, included in perf data with the new
PERF_RECORD_NAMESPACES event, as cgroup identifier. With the assumption
that each container is created with it's own cgroup namespace, this
allows assessment/analysis of multiple containers at once.

Shown below is the output of perf report, sorted based on cgroup id, on
a system that was running three containers at the time of perf record
and clearly showing one of the containers' considerable use of kernel
memory in comparison with others:


	$ perf report -s cgroup_id,sample --stdio
	#
	# Total Lost Samples: 0
	#
	# Samples: 1K of event 'kmem:kmalloc'
	# Event count (approx.): 1232
	#
	# Overhead  cgroup id        Samples
	# ........  ..........  ............
	#
	    86.53%  4026532046          1066
	     5.60%  4026531835            69
	     3.81%  4026532047            47
	     3.81%  4026532048            47
	     0.24%  0                      3

Signed-off-by: Hari Bathini <hbathini@xxxxxxxxxxxxxxxxxx>
---
 tools/perf/util/hist.c |    4 ++++
 tools/perf/util/hist.h |    1 +
 tools/perf/util/sort.c |   22 ++++++++++++++++++++++
 tools/perf/util/sort.h |    2 ++
 4 files changed, 29 insertions(+)

diff --git a/tools/perf/util/hist.c b/tools/perf/util/hist.c
index a69f027..a6650d7 100644
--- a/tools/perf/util/hist.c
+++ b/tools/perf/util/hist.c
@@ -2,6 +2,7 @@
 #include "build-id.h"
 #include "hist.h"
 #include "session.h"
+#include "namespaces.h"
 #include "sort.h"
 #include "evlist.h"
 #include "evsel.h"
@@ -168,6 +169,7 @@ void hists__calc_col_len(struct hists *hists, struct hist_entry *h)
 		hists__set_unres_dso_col_len(hists, HISTC_MEM_DADDR_DSO);
 	}
 
+	hists__new_col_len(hists, HISTC_CGROUP_ID, 10);
 	hists__new_col_len(hists, HISTC_CPU, 3);
 	hists__new_col_len(hists, HISTC_SOCKET, 6);
 	hists__new_col_len(hists, HISTC_MEM_LOCKED, 6);
@@ -573,9 +575,11 @@ __hists__add_entry(struct hists *hists,
 		   bool sample_self,
 		   struct hist_entry_ops *ops)
 {
+	struct namespaces *ns = thread__namespaces(al->thread);
 	struct hist_entry entry = {
 		.thread	= al->thread,
 		.comm = thread__comm(al->thread),
+		.cgroup_id = ns ? ns->inode_num[CGROUP_NS_INDEX] : 0,
 		.ms = {
 			.map	= al->map,
 			.sym	= al->sym,
diff --git a/tools/perf/util/hist.h b/tools/perf/util/hist.h
index 9928fed..894c95d 100644
--- a/tools/perf/util/hist.h
+++ b/tools/perf/util/hist.h
@@ -29,6 +29,7 @@ enum hist_column {
 	HISTC_DSO,
 	HISTC_THREAD,
 	HISTC_COMM,
+	HISTC_CGROUP_ID,
 	HISTC_PARENT,
 	HISTC_CPU,
 	HISTC_SOCKET,
diff --git a/tools/perf/util/sort.c b/tools/perf/util/sort.c
index 452e15a..b6152df 100644
--- a/tools/perf/util/sort.c
+++ b/tools/perf/util/sort.c
@@ -536,6 +536,27 @@ struct sort_entry sort_cpu = {
 	.se_width_idx	= HISTC_CPU,
 };
 
+/* --sort cgroup_id */
+
+static int64_t
+sort__cgroup_id_cmp(struct hist_entry *left, struct hist_entry *right)
+{
+	return (int64_t)right->cgroup_id - (int64_t)left->cgroup_id;
+}
+
+static int hist_entry__cgroup_id_snprintf(struct hist_entry *he, char *bf,
+					  size_t size, unsigned int width)
+{
+	return repsep_snprintf(bf, size, "%-*u", width, he->cgroup_id);
+}
+
+struct sort_entry sort_cgroup_id = {
+	.se_header      = "cgroup id",
+	.se_cmp	        = sort__cgroup_id_cmp,
+	.se_snprintf    = hist_entry__cgroup_id_snprintf,
+	.se_width_idx	= HISTC_CGROUP_ID,
+};
+
 /* --sort socket */
 
 static int64_t
@@ -1418,6 +1439,7 @@ static struct sort_dimension common_sort_dimensions[] = {
 	DIM(SORT_GLOBAL_WEIGHT, "weight", sort_global_weight),
 	DIM(SORT_TRANSACTION, "transaction", sort_transaction),
 	DIM(SORT_TRACE, "trace", sort_trace),
+	DIM(SORT_CGROUP_ID, "cgroup_id", sort_cgroup_id),
 };
 
 #undef DIM
diff --git a/tools/perf/util/sort.h b/tools/perf/util/sort.h
index 099c975..e8058f6 100644
--- a/tools/perf/util/sort.h
+++ b/tools/perf/util/sort.h
@@ -95,6 +95,7 @@ struct hist_entry {
 	u64			transaction;
 	s32			socket;
 	s32			cpu;
+	u32			cgroup_id;
 	u8			cpumode;
 	u8			depth;
 
@@ -211,6 +212,7 @@ enum sort_type {
 	SORT_GLOBAL_WEIGHT,
 	SORT_TRANSACTION,
 	SORT_TRACE,
+	SORT_CGROUP_ID,
 
 	/* branch stack specific sort keys */
 	__SORT_BRANCH_STACK,