perf test bpf-counters: Add test for BPF event modifier

Refactor test to better enable sharing of logic, to give an idea of
progress and introduce test functions. Add test of measuring both
cycles and cycles:b simultaneously.

Signed-off-by: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Athira Rajeev <atrajeev@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ravi Bangoria <ravi.bangoria@amd.com>
Cc: Song Liu <song@kernel.org>
Cc: Thomas Richter <tmricht@linux.ibm.com>
Link: https://lore.kernel.org/r/20240416170014.985191-2-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

Author: captain5050

tools/perf/tests/shell/stat_bpf_counters.sh

@@ -4,21 +4,59 @@
 
 set -e
 
+workload="perf bench sched messaging -g 1 -l 100 -t"
+
 # check whether $2 is within +/- 20% of $1
 compare_number()
 {
-       first_num=$1
-       second_num=$2
-
-       # upper bound is first_num * 120%
-       upper=$(expr $first_num + $first_num / 5 )
-       # lower bound is first_num * 80%
-       lower=$(expr $first_num - $first_num / 5 )
-
-       if [ $second_num -gt $upper ] || [ $second_num -lt $lower ]; then
-               echo "The difference between $first_num and $second_num are greater than 20%."
-               exit 1
-       fi
+	first_num=$1
+	second_num=$2
+
+	# upper bound is first_num * 120%
+	upper=$(expr $first_num + $first_num / 5 )
+	# lower bound is first_num * 80%
+	lower=$(expr $first_num - $first_num / 5 )
+
+	if [ $second_num -gt $upper ] || [ $second_num -lt $lower ]; then
+		echo "The difference between $first_num and $second_num are greater than 20%."
+		exit 1
+	fi
+}
+
+check_counts()
+{
+	base_cycles=$1
+	bpf_cycles=$2
+
+	if [ "$base_cycles" = "<not" ]; then
+		echo "Skipping: cycles event not counted"
+		exit 2
+	fi
+	if [ "$bpf_cycles" = "<not" ]; then
+		echo "Failed: cycles not counted with --bpf-counters"
+		exit 1
+	fi
+}
+
+test_bpf_counters()
+{
+	printf "Testing --bpf-counters "
+	base_cycles=$(perf stat --no-big-num -e cycles -- $workload 2>&1 | awk '/cycles/ {print $1}')
+	bpf_cycles=$(perf stat --no-big-num --bpf-counters -e cycles -- $workload  2>&1 | awk '/cycles/ {print $1}')
+	check_counts $base_cycles $bpf_cycles
+	compare_number $base_cycles $bpf_cycles
+	echo "[Success]"
+}
+
+test_bpf_modifier()
+{
+	printf "Testing bpf event modifier "
+	stat_output=$(perf stat --no-big-num -e cycles/name=base_cycles/,cycles/name=bpf_cycles/b -- $workload 2>&1)
+	base_cycles=$(echo "$stat_output"| awk '/base_cycles/ {print $1}')
+	bpf_cycles=$(echo "$stat_output"| awk '/bpf_cycles/ {print $1}')
+	check_counts $base_cycles $bpf_cycles
+	compare_number $base_cycles $bpf_cycles
+	echo "[Success]"
 }
 
 # skip if --bpf-counters is not supported
@@ -30,16 +68,7 @@ if ! perf stat -e cycles --bpf-counters true > /dev/null 2>&1; then
 	exit 2
 fi
 
-base_cycles=$(perf stat --no-big-num -e cycles -- perf bench sched messaging -g 1 -l 100 -t 2>&1 | awk '/cycles/ {print $1}')
-if [ "$base_cycles" = "<not" ]; then
-	echo "Skipping: cycles event not counted"
-	exit 2
-fi
-bpf_cycles=$(perf stat --no-big-num --bpf-counters -e cycles -- perf bench sched messaging -g 1 -l 100 -t 2>&1 | awk '/cycles/ {print $1}')
-if [ "$bpf_cycles" = "<not" ]; then
-	echo "Failed: cycles not counted with --bpf-counters"
-	exit 1
-fi
+test_bpf_counters
+test_bpf_modifier
 
-compare_number $base_cycles $bpf_cycles
 exit 0