[PATCH v1 1/9] selftests/resctrl: Verify all RMIDs count together

[Peter Newman <peternewman@google.com>]

AMD CPUs in particular implement fewer monitors than RMIDs, so add a
test case to see if a large number of monitoring groups can be measured
together.

Signed-off-by: Peter Newman <peternewman@google.com>
---
 tools/testing/selftests/resctrl/test_rmids.sh | 93 +++++++++++++++++++
 1 file changed, 93 insertions(+)
 create mode 100755 tools/testing/selftests/resctrl/test_rmids.sh

diff --git a/tools/testing/selftests/resctrl/test_rmids.sh b/tools/testing/selftests/resctrl/test_rmids.sh
new file mode 100755
index 000000000000..475e69c0217e
--- /dev/null
+++ b/tools/testing/selftests/resctrl/test_rmids.sh
@@ -0,0 +1,93 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0
+
+cd /sys/fs/resctrl
+
+grep -q mbm_total_bytes info/L3_MON/mon_features || {
+	echo "MBM required"
+	exit 4
+}
+
+which perf > /dev/null || {
+	echo "perf tool required"
+	exit 4
+}
+
+num_rmids=$(cat info/L3_MON/num_rmids)
+
+count=0
+
+result=0
+
+# use as many RMIDs as possible, up to the number of RMIDs
+for i in `seq $num_rmids`; do
+	mkdir mon_groups/_test_m$((count+1)) 2> /dev/null || break
+	if [[ -d mon_groups/_test_m$((count+1))/mon_data ]]; then
+		count=$((count+1))
+	else
+		break;
+	fi
+done
+
+echo "Created $count monitoring groups."
+
+if [[ $count -eq 0 ]]; then
+	echo "need monitoring groups to continue."
+	exit 4
+fi
+
+declare -a bytes_array
+
+unavailable=0
+unavailable0=0
+
+for i in `seq $count`; do
+	bytes_array[$i]=$(cat mon_groups/_test_m${i}/mon_data/mon_L3_00/mbm_total_bytes)
+
+	if [[ "${bytes_array[$i]}" = "Unavailable" ]]; then
+		unavailable0=$((unavailable0 + 1))
+	fi
+done
+
+for i in `seq $count`; do
+	echo $$ > mon_groups/_test_m${i}/tasks
+	taskset 0x1 perf bench mem memcpy -s 100MB -f default > /dev/null
+done
+echo $$ > tasks
+
+# zero non-integer values
+declare -i bytes bytes0
+
+success_count=0
+
+for i in `seq $count`; do
+	raw_bytes=$(cat mon_groups/_test_m${i}/mon_data/mon_L3_00/mbm_total_bytes)
+	raw_bytes0=${bytes_array[$i]}
+
+	# coerce the value to an integer for math
+	bytes=$raw_bytes
+	bytes0=$raw_bytes0
+
+	echo -n "g${i}: mbm_total_bytes: $raw_bytes0 -> $raw_bytes"
+
+	if [[ "$raw_bytes" = "Unavailable" ]]; then
+		unavailable=$((unavailable + 1))
+	fi
+
+	if [[ $bytes -gt $bytes0 ]]; then
+		success_count=$((success_count+1))
+		echo ""
+	else
+		echo " (FAIL)"
+		result=1
+	fi
+done
+
+first=$((count-unavailable0))
+second=$((count-unavailable))
+echo "$count groups, $first returned counts in first pass, $second in second"
+echo "successfully measured bandwidth from ${success_count}/${count} groups"
+
+rmdir mon_groups/_test_m*
+
+exit $result
-- 
2.40.0.634.g4ca3ef3211-goog