perf tests arm_spe: Add test for discard mode

JIRA: https://issues.redhat.com/browse/RHEL-77936

upstream
========
commit 05cd60e
Author: James Clark <[email protected]>
Date: Wed Jan 8 14:29:00 2025 +0000

description
===========
Add a test that checks that there were no AUX or AUXTRACE events
recorded when discard mode is used.

    Reviewed-by: Yeoreum Yun <[email protected]>
    Signed-off-by: James Clark <[email protected]>
    Cc: Adrian Hunter <[email protected]>
    Cc: Alexander Shishkin <[email protected]>
    Cc: Athira Rajeev <[email protected]>
    Cc: Graham Woodward <[email protected]>
    Cc: Ian Rogers <[email protected]>
    Cc: Ingo Molnar <[email protected]>
    Cc: Jiri Olsa <[email protected]>
    Cc: John Garry <[email protected]>
    Cc: Kan Liang <[email protected]>
    Cc: Leo Yan <[email protected]>
    Cc: Mark Rutland <[email protected]>
    Cc: Michael Petlan <[email protected]>
    Cc: Mike Leach <[email protected]>
    Cc: Namhyung Kim <[email protected]>
    Cc: Peter Zijlstra <[email protected]>
    Cc: Rob Herring <[email protected]>
    Cc: Thomas Richter <[email protected]>
    Cc: Veronika Molnarova <[email protected]>
    Cc: Will Deacon <[email protected]>
    Link: https://lore.kernel.org/r/[email protected]
    Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Signed-off-by: Michael Petlan <[email protected]>

Author: rfmvh

tools/perf/tests/shell/test_arm_spe.sh

@@ -107,7 +107,37 @@ arm_spe_system_wide_test() {
 	arm_spe_report "SPE system-wide testing" $err
 }
 
+arm_spe_discard_test() {
+	echo "SPE discard mode"
+
+	for f in /sys/bus/event_source/devices/arm_spe_*; do
+		if [ -e "$f/format/discard" ]; then
+			cpu=$(cut -c -1 "$f/cpumask")
+			break
+		fi
+	done
+
+	if [ -z $cpu ]; then
+		arm_spe_report "SPE discard mode not present" 2
+		return
+	fi
+
+	# Test can use wildcard SPE instance and Perf will only open the event
+	# on instances that have that format flag. But make sure the target
+	# runs on an instance with discard mode otherwise we're not testing
+	# anything.
+	perf record -o ${perfdata} -e arm_spe/discard/ -N -B --no-bpf-event \
+		-- taskset --cpu-list $cpu true
+
+	if perf report -i ${perfdata} --stats | grep 'AUX events\|AUXTRACE events'; then
+		arm_spe_report "SPE discard mode found unexpected data" 1
+	else
+		arm_spe_report "SPE discard mode" 0
+	fi
+}
+
 arm_spe_snapshot_test
 arm_spe_system_wide_test
+arm_spe_discard_test
 
 exit $glb_err