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 <[email protected]>
---
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
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 <[email protected]>
---
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