kernel/git/stable/linux.git/tools/perf/tests, branch linux-5.15.y

perf tests: Fix flakiness in BPF counters test on hybrid systems

2026-09-14T11:20:26+00:00

[ Upstream commit b02027776ac5bf737f1b76f3759f405e376097e5 ] The `perf stat --bpf-counters test` fails intermittently on hybrid architectures or systems with dynamic frequency scaling (DVFS). This happens because the test workload (`sqrtloop`) runs for a fixed 1-second duration, and the CPU frequency can scale dynamically between idle and maximum frequency. As the first run runs on a cold CPU and the second run runs on a warmed-up CPU (or vice versa), the number of instructions executed in 1 second differs by up to 2.2x, violating the comparison tolerance. Also, when running as root, BPF tracepoints and scheduling programs trigger frequently. Since standard `perf stat -e instructions` measures both user and kernel space instructions, it counts BPF helper and program execution overheads, whereas the BPF counters themselves do not self- measure. This introduces a large kernel-space instruction count discrepancy between standard and BPF counters. Fix these issues by: 1. Switching the workload to a strictly deterministic, iteration-based workload: `awk 'BEGIN { for (i=0; i<10000000; i++) sum+=i }'`. We pin the workload to a single random allowed CPU using `taskset -c $CPU` via a bash array. 2. Restricting the counted event to user-space only (`instructions:u` or `/u`). 3. Tightening the comparison tolerance from 20% to 15%. These modifications isolate the measurements to user-space instructions of the deterministic loop, which executes a virtually identical number of instructions on both runs (with less than 0.001% variation), eliminating Dynamic Frequency Scaling (DVFS), kernel scheduling noise, and BPF helper self-measurement overheads. Fixes: 2c0cb9f56020 ("perf test: Add a shell test for 'perf stat --bpf-counters' new option") Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf test: Fix perf stat --bpf-counters on hybrid machines

2026-09-14T11:20:26+00:00

[ Upstream commit d9db9c8db56c3e378aa5c91637664f77ca5a6f72 ] The test constantly fails on my Intel hybrid machine. The issue was it has two events in the output even if I only gave it one event. $ perf stat -e instructions -- perf test -w sqrtloop Performance counter stats for 'perf test -w sqrtloop': 910,856,421 cpu_atom/instructions/ (28.05%) 14,852,865,997 cpu_core/instructions/ (96.79%) 1.014313341 seconds time elapsed 1.004114000 seconds user 0.008174000 seconds sys Let's modify the awk script to add the values for each line and print the total. The variable 'i' has a number of input lines that have valid output and variable 'c' has the sum of actual counter values. That way it should work on any platforms. Reviewed-by: Ian Rogers Signed-off-by: Namhyung Kim Stable-dep-of: b02027776ac5 ("perf tests: Fix flakiness in BPF counters test on hybrid systems") Signed-off-by: Sasha Levin

perf test: Use sqrtloop workload to test bperf event

2026-09-14T11:20:26+00:00

[ Upstream commit d36e5b36a2928b30e09ff59ce5ce2d5df935176e ] Replace `brstack` workload with `sqrtloop` workload, because `sqrtloop` workload contains fork(), which is suitable for testing the bperf event inheritance feature. Signed-off-by: Tengda Wu Cc: song@kernel.org Cc: bpf@vger.kernel.org Link: https://lore.kernel.org/r/20241021110201.325617-3-wutengda@huaweicloud.com Signed-off-by: Namhyung Kim Stable-dep-of: b02027776ac5 ("perf tests: Fix flakiness in BPF counters test on hybrid systems") Signed-off-by: Sasha Levin

perf test stat_bpf_counter.sh: Stabilize the test results

2026-09-14T11:20:26+00:00

[ Upstream commit e8b86f0311a4b721663df8105a680e5968f21d4c ] The test has been failing for some time when two separate runs of perf benchmarks are recorded for cycles events and their counts are compared, while once the recording was done with option --bpf-counters and once without it. It is expected that the count of the samples should be within a certain range, firstly the difference was set to be within 10%, which was then later raised to 20%. However, the test case keeps failing on certain architectures as recording the provided benchmark can produce completely different counts based on the current load of the system. Sampling two separate runs on intel-eaglestream-spr-13 of "perf stat --no-big-num -e cycles -- perf bench sched messaging -g 1 -l 100 -t": Performance counter stats for 'perf bench sched messaging -g 1 -l 100 -t': 396782898 cycles 0.010051983 seconds time elapsed 0.008664000 seconds user 0.097058000 seconds sys Performance counter stats for 'perf bench sched messaging -g 1 -l 100 -t': 1431133032 cycles 0.021803714 seconds time elapsed 0.023377000 seconds user 0.349918000 seconds sys , which is ranging from 400mil to 1400mil samples. Instead of recording the cycles use instructions event, which provides more stable values. At the same time change the tested workload to one of the provided testing workloads by perf that is not based on a scheduler, which can provide another dependency on the current load. Sampling instructions event with the new workload provide much more stable results on intel-eaglestream-spr-13 of "perf stat --no-big-num -e instructions -- perf test -w brstack": Performance counter stats for 'perf test -w brstack': 64584494 instructions 0.009173945 seconds time elapsed 0.007262000 seconds user 0.002071000 seconds sys Performance counter stats for 'perf test -w brstack': 64672669 instructions 0.008888135 seconds time elapsed 0.005018000 seconds user 0.004018000 seconds sys Signed-off-by: Veronika Molnarova Acked-by: Namhyung Kim Cc: mpetlan@redhat.com Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240625092001.10909-1-vmolnaro@redhat.com Stable-dep-of: b02027776ac5 ("perf tests: Fix flakiness in BPF counters test on hybrid systems") Signed-off-by: Sasha Levin

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

2026-09-14T11:20:26+00:00

[ Upstream commit d9bd1d4264baddf7ab8baae86e91674d369f22de ] 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 Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Ravi Bangoria Cc: Song Liu Cc: Thomas Richter Link: https://lore.kernel.org/r/20240416170014.985191-2-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo Stable-dep-of: b02027776ac5 ("perf tests: Fix flakiness in BPF counters test on hybrid systems") Signed-off-by: Sasha Levin

perf test: raise limit to 20 percent for perf_stat_--bpf-counters_test

2026-09-14T11:20:25+00:00

[ Upstream commit 999eea92e8d7a1ffa83f7dc89c83d8ed1e746fa9 ] This test case often fails on s390 (about 2 out of 10) because the 10% percent limit on the difference between --bpf-counters event counting and s390 hardware counting is more than 10% in all failure cases. Raise the limit to 20% on s390 and the test case succeeds. Signed-off-by: Thomas Richter Acked-by: Namhyung Kim Cc: gor@linux.ibm.com Cc: hca@linux.ibm.com Cc: sumanthk@linux.ibm.com Cc: svens@linux.ibm.com Link: https://lore.kernel.org/r/20240108084009.3959211-1-tmricht@linux.ibm.com Signed-off-by: Namhyung Kim Stable-dep-of: b02027776ac5 ("perf tests: Fix flakiness in BPF counters test on hybrid systems") Signed-off-by: Sasha Levin

perf tests stat_bpf_counters: Fix usage of '==' to address shellcheck warning

2026-09-14T11:20:25+00:00

[ Upstream commit d10eedd87bb3e7678c3a0f77a5cfe7150a318ee2 ] Running shellcheck on stat_bpf_counter.sh generates below warning: In tests/shell/stat_bpf_counters.sh line 34: if [ "$base_cycles" == "

Revert "perf test: Don't leak workload gopipe in PERF_RECORD_*"

2025-10-29T13:03:09+00:00

This reverts commit b7e5c59f3b0971f56ebbceb9d42cc45e9ac1cd94 which is commit 48918cacefd226af44373e914e63304927c0e7dc upstream. Commit in question broke building perf followingly with v5.15.195: | ld: perf-in.o: in function `test__PERF_RECORD': | tools/perf/tests/perf-record.c:142: undefined reference to `evlist__cancel_workload' The 'evlist__cancel_workload' seems to be introduced in commit e880a70f8046 ("perf stat: Close cork_fd when create_perf_stat_counter() failed") which is currently not included in the 5.15 stable series. Fixes: b7e5c59f3b09 ("perf test: Don't leak workload gopipe in PERF_RECORD_*") Cc: stable@vger.kernel.org # 5.15 Signed-off-by: Niko Mauno Signed-off-by: Greg Kroah-Hartman

perf test: Don't leak workload gopipe in PERF_RECORD_*

2025-10-19T14:21:40+00:00

[ Upstream commit 48918cacefd226af44373e914e63304927c0e7dc ] The test starts a workload and then opens events. If the events fail to open, for example because of perf_event_paranoid, the gopipe of the workload is leaked and the file descriptor leak check fails when the test exits. To avoid this cancel the workload when opening the events fails. Before: ``` $ perf test -vv 7 7: PERF_RECORD_* events & perf_sample fields: --- start --- test child forked, pid 1189568 Using CPUID GenuineIntel-6-B7-1 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0xa00000000 (cpu_atom/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 exclude_kernel 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 = 3 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 ------------------------------------------------------------ perf_event_attr: type 0 (PERF_TYPE_HARDWARE) config 0x400000000 (cpu_core/PERF_COUNT_HW_CPU_CYCLES/) disabled 1 exclude_kernel 1 ------------------------------------------------------------ sys_perf_event_open: pid 0 cpu -1 group_fd -1 flags 0x8 = 3 Attempt to add: software/cpu-clock/ ..after resolving event: software/config=0/ cpu-clock -> software/cpu-clock/ ------------------------------------------------------------ perf_event_attr: type 1 (PERF_TYPE_SOFTWARE) size 136 config 0x9 (PERF_COUNT_SW_DUMMY) sample_type IP|TID|TIME|CPU read_format ID|LOST disabled 1 inherit 1 mmap 1 comm 1 enable_on_exec 1 task 1 sample_id_all 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 { wakeup_events, wakeup_watermark } 1 ------------------------------------------------------------ sys_perf_event_open: pid 1189569 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 perf_evlist__open: Permission denied ---- end(-2) ---- Leak of file descriptor 6 that opened: 'pipe:[14200347]' ---- unexpected signal (6) ---- iFailed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon Failed to read build ID for //anon #0 0x565358f6666e in child_test_sig_handler builtin-test.c:311 #1 0x7f29ce849df0 in __restore_rt libc_sigaction.c:0 #2 0x7f29ce89e95c in __pthread_kill_implementation pthread_kill.c:44 #3 0x7f29ce849cc2 in raise raise.c:27 #4 0x7f29ce8324ac in abort abort.c:81 #5 0x565358f662d4 in check_leaks builtin-test.c:226 #6 0x565358f6682e in run_test_child builtin-test.c:344 #7 0x565358ef7121 in start_command run-command.c:128 #8 0x565358f67273 in start_test builtin-test.c:545 #9 0x565358f6771d in __cmd_test builtin-test.c:647 #10 0x565358f682bd in cmd_test builtin-test.c:849 #11 0x565358ee5ded in run_builtin perf.c:349 #12 0x565358ee6085 in handle_internal_command perf.c:401 #13 0x565358ee61de in run_argv perf.c:448 #14 0x565358ee6527 in main perf.c:555 #15 0x7f29ce833ca8 in __libc_start_call_main libc_start_call_main.h:74 #16 0x7f29ce833d65 in __libc_start_main@@GLIBC_2.34 libc-start.c:128 #17 0x565358e391c1 in _start perf[851c1] 7: PERF_RECORD_* events & perf_sample fields : FAILED! ``` After: ``` $ perf test 7 7: PERF_RECORD_* events & perf_sample fields : Skip (permissions) ``` Fixes: 16d00fee703866c6 ("perf tests: Move test__PERF_RECORD into separate object") Signed-off-by: Ian Rogers Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Athira Rajeev 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 Signed-off-by: Sasha Levin

perf tests bp_account: Fix leaked file descriptor

2025-08-28T14:24:10+00:00

[ Upstream commit 4a6cdecaa1497f1fbbd1d5307a225b6ca5a62a90 ] Since the commit e9846f5ead26 ("perf test: In forked mode add check that fds aren't leaked"), the test "Breakpoint accounting" reports the error: # perf test -vvv "Breakpoint accounting" 20: Breakpoint accounting: --- start --- test child forked, pid 373 failed opening event 0 failed opening event 0 watchpoints count 4, breakpoints count 6, has_ioctl 1, share 0 wp 0 created wp 1 created wp 2 created wp 3 created wp 0 modified to bp wp max created ---- end(0) ---- Leak of file descriptor 7 that opened: 'anon_inode:[perf_event]' A watchpoint's file descriptor was not properly released. This patch fixes the leak. Fixes: 032db28e5fa3 ("perf tests: Add breakpoint accounting/modify test") Reported-by: Aishwarya TCV Signed-off-by: Leo Yan Reviewed-by: Ian Rogers Link: https://lore.kernel.org/r/20250711-perf_fix_breakpoint_accounting-v1-1-b314393023f9@arm.com Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin