[PATCH v1 1/2] perf docs: Document bpf event modifier

[PATCH v1 1/2] perf docs: Document bpf event modifier

[Ian Rogers]

Document that 'b' is used as a modifier to make an event use a BPF
counter.

Fixes: 01bd8efcec44 ("perf stat: Introduce ':b' modifier")
Signed-off-by: Ian Rogers <irogers@google.com>
---
 tools/perf/Documentation/perf-list.txt | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/Documentation/perf-list.txt b/tools/perf/Documentation/perf-list.txt
index 3b12595193c9..6bf2468f59d3 100644
--- a/tools/perf/Documentation/perf-list.txt
+++ b/tools/perf/Documentation/perf-list.txt
@@ -71,6 +71,7 @@ counted. The following modifiers exist:
  D - pin the event to the PMU
  W - group is weak and will fallback to non-group if not schedulable,
  e - group or event are exclusive and do not share the PMU
+ b - use BPF aggregration (see perf stat --bpf-counters)
 
 The 'p' modifier can be used for specifying how precise the instruction
 address should be. The 'p' modifier can be specified multiple times:
-- 
2.44.0.683.g7961c838ac-goog

[PATCH v1 2/2] perf test bpf-counters: Add test for BPF event modifier

[Ian Rogers]

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>
---
 tools/perf/tests/shell/stat_bpf_counters.sh | 75 ++++++++++++++-------
 1 file changed, 52 insertions(+), 23 deletions(-)

diff --git a/tools/perf/tests/shell/stat_bpf_counters.sh b/tools/perf/tests/shell/stat_bpf_counters.sh
index 2d9209874774..61f8149d854e 100755
--- a/tools/perf/tests/shell/stat_bpf_counters.sh
+++ b/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
-- 
2.44.0.683.g7961c838ac-goog