kernel/linux.git/tools/perf/tests/shell/record_lbr.sh, branch v7.1

perf test shell lbr: Avoid failures with perf event paranoia

2025-09-19T15:14:30+00:00

When not running as root and with higher perf event paranoia values the perf record LBR tests could fail rather than skipping the problematic tests. Add the sensitivity to the test and confirm it passes with paranoia values from -1 to 2. Committer testing: Testing with '$ perf test -vv lbr', i.e. as non root, and then comparing the output shows the mentioned errors before this patch: acme@x1:~$ grep -m1 "model name" /proc/cpuinfo model name : 13th Gen Intel(R) Core(TM) i7-1365U acme@x1:~$ Before: 132: perf record LBR tests : Skip After: 132: perf record LBR tests : Ok Fixes: 32559b99e0f59070 ("perf test: Add set of perf record LBR tests") Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Chun-Tse Shao Cc: Howard Chu Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo

perf test: Update sysfs path for core PMU caps

2025-05-13T20:45:35+00:00

While CPU is a system device, it'd be better to use a path for event_source devices when it checks PMU capability. Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250509213017.204343-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf test: Fix LBR test by ignoring idle task

2025-05-13T20:45:11+00:00

I found 'perf record LBR tests' failing due to empty branch stacks. $ perf test -v LBR ... LBR system wide any branch test Lowering default frequency rate from 4000 to 1000. Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. [ perf record: Woken up 8 times to write data ] [ perf record: Captured and wrote 3.142 MB /tmp/__perf_test.perf.data.dgSBl (3572 samples) ] LBR system wide any branch test: 3572 samples LBR system wide any branch test [Failed empty br stack ratio exceed 2%: 3%] LBR system wide any call test Lowering default frequency rate from 4000 to 1000. Please consider tweaking /proc/sys/kernel/perf_event_max_sample_rate. [ perf record: Woken up 8 times to write data ] [ perf record: Captured and wrote 3.337 MB /tmp/__perf_test.perf.data.dgSBl (3967 samples) ] LBR system wide any call test: 3967 samples LBR system wide any call test [Failed empty br stack ratio exceed 2%: 9%] ... The failing cases were in system-wide mode and I realized that the samples were from the idle tasks (swapper). I suspect going to/from idle state may affect the LBR contents. If we can skip empty branch stacks from the idle tasks, the failure should go away. I can see the following output in perf report -D. $ perf report -D | grep -m5 -A3 'branch stack: nr:0' ... -- ... branch stack: nr:0 ... thread: swapper:0 ...... dso: /proc/kcore -- ... branch stack: nr:0 ... thread: swapper:0 ...... dso: /proc/kcore -- ... branch stack: nr:0 ... thread: DefaultEventMan:10282 ...... dso: /proc/kcore -- ... branch stack: nr:0 ... thread: swapper:0 ...... dso: /proc/kcore -- ... branch stack: nr:0 ... thread: swapper:0 ...... dso: /proc/kcore $ perf report -D | grep -c 'branch stack: nr:0' 145 $ perf report -D | grep -A3 'branch stack: nr:0' | grep thread | grep -c swapper i36 $ perf report -D | grep -A3 'branch stack: nr:0' | grep thread | grep -cv swapper 9 Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim Cc: Adrian Hunter Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250509213017.204343-1-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf test: Tag parallel failing shell tests with "(exclusive)"

2024-10-28T16:32:58+00:00

Some shell tests compete for resources and so can't run with other tests, tag such tests. The "(exclusive)" stems from shared/exclusive to describe how the tests run as if holding a lock. For ARM/coresight tests: Suggested-by: James Clark Additional failing tests: Suggested-by: Namhyung Kim Tested-by: James Clark Signed-off-by: Ian Rogers Cc: Colin Ian King Cc: Howard Chu Cc: Weilin Wang Cc: Ilya Leoshkevich Cc: Thomas Richter Cc: Andi Kleen Cc: Dapeng Mi Cc: Athira Jajeev Cc: Michael Petlan Cc: Veronika Molnarova Link: https://lore.kernel.org/r/20241025192109.132482-6-irogers@google.com Signed-off-by: Namhyung Kim

perf test shell lbr: Support hybrid x86 systems too

2024-08-08T20:30:39+00:00

Running on a: root@x1:~# grep 'model name' -m1 /proc/cpuinfo model name : 13th Gen Intel(R) Core(TM) i7-1365U root@x1:~# It skips all the tests with: root@x1:~# perf test -vvvv LBR 97: perf record LBR tests: --- start --- test child forked, pid 2033388 Skip: only x86 CPUs support LBR ---- end(-2) ---- 97: perf record LBR tests : Skip root@x1:~# Because the test checks for the /sys/devices/cpu/caps/branches file, that isn't present as we have instead: root@x1:~# ls -la /sys/devices/cpu*/caps/branches -r--r--r--. 1 root root 4096 Aug 8 11:22 /sys/devices/cpu_atom/caps/branches -r--r--r--. 1 root root 4096 Aug 8 11:21 /sys/devices/cpu_core/caps/branches root@x1:~# If we check as well for one of those, /sys/devices/cpu_core/caps/branches, then we don't skip the tests and all are run on these x86 Intel Hybrid systems as well, passing all of them: root@x1:~# perf test -vvvv LBR 97: perf record LBR tests: --- start --- test child forked, pid 2034956 LBR callgraph [ perf record: Woken up 5 times to write data ] [ perf record: Captured and wrote 1.812 MB /tmp/__perf_test.perf.data.B2HvQ (8114 samples) ] LBR callgraph [Success] LBR any branch test [ perf record: Woken up 25 times to write data ] [ perf record: Captured and wrote 6.382 MB /tmp/__perf_test.perf.data.B2HvQ (8071 samples) ] LBR any branch test: 8071 samples LBR any branch test [Success] LBR any call test [ perf record: Woken up 23 times to write data ] [ perf record: Captured and wrote 6.208 MB /tmp/__perf_test.perf.data.B2HvQ (8092 samples) ] LBR any call test: 8092 samples LBR any call test [Success] LBR any ret test [ perf record: Woken up 24 times to write data ] [ perf record: Captured and wrote 6.396 MB /tmp/__perf_test.perf.data.B2HvQ (8093 samples) ] LBR any ret test: 8093 samples LBR any ret test [Success] LBR any indirect call test [ perf record: Woken up 25 times to write data ] [ perf record: Captured and wrote 6.344 MB /tmp/__perf_test.perf.data.B2HvQ (8067 samples) ] LBR any indirect call test: 8067 samples LBR any indirect call test [Success] LBR any indirect jump test [ perf record: Woken up 12 times to write data ] [ perf record: Captured and wrote 3.073 MB /tmp/__perf_test.perf.data.B2HvQ (8061 samples) ] LBR any indirect jump test: 8061 samples LBR any indirect jump test [Success] LBR direct calls test [ perf record: Woken up 25 times to write data ] [ perf record: Captured and wrote 6.380 MB /tmp/__perf_test.perf.data.B2HvQ (8076 samples) ] LBR direct calls test: 8076 samples LBR direct calls test [Success] LBR any indirect user call test [ perf record: Woken up 5 times to write data ] [ perf record: Captured and wrote 1.597 MB /tmp/__perf_test.perf.data.B2HvQ (8079 samples) ] LBR any indirect user call test: 8079 samples LBR any indirect user call test [Success] LBR system wide any branch test [ perf record: Woken up 26 times to write data ] [ perf record: Captured and wrote 9.088 MB /tmp/__perf_test.perf.data.B2HvQ (9209 samples) ] LBR system wide any branch test: 9209 samples LBR system wide any branch test [Success] LBR system wide any call test [ perf record: Woken up 25 times to write data ] [ perf record: Captured and wrote 8.945 MB /tmp/__perf_test.perf.data.B2HvQ (9333 samples) ] LBR system wide any call test: 9333 samples LBR system wide any call test [Success] LBR parallel any branch test LBR parallel any call test LBR parallel any ret test LBR parallel any indirect call test LBR parallel any indirect jump test LBR parallel direct calls test LBR parallel system wide any branch test LBR parallel any indirect user call test LBR parallel system wide any call test [ perf record: Woken up 9 times to write data ] [ perf record: Woken up 51 times to write data ] [ perf record: Woken up 1 times to write data ] [ perf record: Woken up 5 times to write data ] [ perf record: Woken up 559 times to write data ] [ perf record: Woken up 14 times to write data ] [ perf record: Woken up 17 times to write data ] [ perf record: Woken up 1 times to write data ] [ perf record: Woken up 11 times to write data ] [ perf record: Captured and wrote 0.150 MB /tmp/__perf_test.perf.data.lANpR (1909 samples) ] [ perf record: Captured and wrote 2.371 MB /tmp/__perf_test.perf.data.Olum8 (3033 samples) ] [ perf record: Captured and wrote 1.230 MB /tmp/__perf_test.perf.data.njfJ8 (1742 samples) ] [ perf record: Captured and wrote 5.554 MB /tmp/__perf_test.perf.data.4ZTrj (29662 samples) ] [ perf record: Captured and wrote 19.906 MB /tmp/__perf_test.perf.data.dlGQt (29576 samples) ] [ perf record: Captured and wrote 0.289 MB /tmp/__perf_test.perf.data.CAT7y (4311 samples) ] [ perf record: Captured and wrote 3.129 MB /tmp/__perf_test.perf.data.diuKG (3971 samples) ] LBR parallel any indirect user call test: 1909 samples [ perf record: Captured and wrote 4.858 MB /tmp/__perf_test.perf.data.sVjtN (6130 samples) ] LBR parallel any indirect user call test [Success] [ perf record: Captured and wrote 3.669 MB /tmp/__perf_test.perf.data.AJtNI (4827 samples) ] LBR parallel any indirect jump test: 4311 samples LBR parallel any indirect jump test [Success] LBR parallel direct calls test: 3033 samples LBR parallel direct calls test [Success] LBR parallel any indirect call test: 1742 samples LBR parallel any indirect call test [Success] LBR parallel any call test: 4827 samples LBR parallel any call test [Success] LBR parallel any branch test: 6130 samples LBR parallel any branch test [Success] LBR parallel system wide any branch test: 29662 samples LBR parallel any ret test: 3971 samples LBR parallel any ret test [Success] LBR parallel system wide any branch test [Success] LBR parallel system wide any call test: 29576 samples LBR parallel system wide any call test [Success] ---- end(0) ---- 97: perf record LBR tests : Ok root@x1:~# Reviewed-by: Kan Liang Acked-by: Ian Rogers Cc: Adrian Hunter Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lore.kernel.org/lkml/ZrTXftup0H46R8WK@x1 Signed-off-by: Arnaldo Carvalho de Melo

perf test: Add set of perf record LBR tests

2024-08-08T20:30:38+00:00

Adds coverage for LBR operations and LBR callgraph. Reviewed-by: Kan Liang Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Andi Kleen Cc: Anne Macedo Cc: Changbin Du Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20240808054644.1286065-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo