kernel/git/stable/linux.git/tools/perf/tests, branch linux-6.18.y

perf tests kvm: Avoid leaving perf.data.guest file around

2026-09-14T11:36:16+00:00

[ Upstream commit b3d1dcd02c8cc1da723c1e9a6b74849ed94b6d30 ] Ensure the perf.data output when checking permissions is written to /dev/null so that it isn't left in the directory the test is run. Fixes: b58261584d2f ("perf test kvm: Add some basic perf kvm test coverage") Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf test: Fix skiplist leak in cmd_test

2026-09-14T11:35:46+00:00

[ Upstream commit 44e82c4d2ff37f073946b594840fd549ab6b9fb8 ] Fix a memory leak in cmd_test() where skiplist was not freed on exit paths. Assisted-by: Antigravity:gemini-3.1-pro Fixes: 2ae828786c65 ("perf test: Allow skipping tests") Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf test: Support dynamic test suites with setup callback and private data

2026-09-14T11:35:46+00:00

[ Upstream commit 8c8d61c38d8e1755a4325f8acb396137bbd5371a ] Add void *priv to struct test_case to allow passing per-test context. Add int (*setup)(struct test_suite *) to struct test_suite to allow dynamic generation of test cases. Update build_suites() to invoke the setup callback for each suite if present, ensuring dynamic cases are available before listing or running. Assisted-by: Gemini-CLI:Google Gemini 3 Signed-off-by: Ian Rogers Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: Namhyung Kim Cc: Peter Zijlstra Signed-off-by: Arnaldo Carvalho de Melo Stable-dep-of: 44e82c4d2ff3 ("perf test: Fix skiplist leak in cmd_test") Signed-off-by: Sasha Levin

perf record: Fix multiple PERF_RECORD_COMPRESSED2 records per push

2026-09-14T11:34:39+00:00

[ Upstream commit ad40a000ea598f316ddc0e81e5acc77cc3b1fae0 ] With Zstd compression enabled ('perf record -z'), a single mmap push whose compressed output exceeds the maximum record size makes zstd_compress_stream_to_records() emit several PERF_RECORD_COMPRESSED2 records back to back. record__pushfn() however rewrote only the first record's header to describe the whole blob as one record: event->data_size = compressed - sizeof(struct perf_record_compressed2); event->header.size = PERF_ALIGN(compressed, sizeof(u64)); padding = event->header.size - compressed; ... record__write(rec, map, &pad, padding); perf_event_header::size is a __u16, so once the compressed blob no longer fits in it the header.size assignment truncates and 'padding' (size_t) underflows. write() is then handed that bogus length and fails with EFAULT, aborting the recording: failed to write perf data, error: Bad address The bytes that did reach the file are mis-framed, so reading it back cannot be decompressed. This is easy to hit with a high event rate and a large buffer, e.g.: perf record -z -F max -m 32M --per-thread -- perf test -w thloop 5 1 The single-record fixup is wrong by construction: because header.size is 16 bits a compressed record cannot exceed 64KB, so the compressor must split a push into a chain of records, and the session reader already consumes them as such. Frame each record where it is produced instead: make process_comp_header() set the per-record data_size, 8-byte-align header.size and zero the trailing padding, and let record__pushfn() write the resulting blob, as the AIO path already does. Reduce max_record_size by sizeof(u64) so the per-record alignment padding cannot push header.size past its u16 field. process_comp_header() returns -1 when that padding would not fit the space left in 'dst', so the compressor stops instead of overrunning the output buffer. There is no on-disk format change; a perf.data written by the fixed tool is still read by existing perf. Fixes: 208c0e168344 ("perf record: Add 8-byte aligned event type PERF_RECORD_COMPRESSED2") Reported-by: Farid Zakaria Signed-off-by: Dmitry Ilvokhin Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf tests: Fix flakiness in branch stack sampling tests

2026-09-14T11:34:26+00:00

[ Upstream commit 344d3aec164dba83a5520f23a0d46e13e904a205 ] The branch stack sampling test (test 130) runs short iteration-based workloads to verify syscall, kernel, and trap branch stack sampling. Specifically, `test_syscall()` and `test_kernel_branches()` run `perf bench syscall basic` with loop counts of 8000 and 1000, and `test_trap_eret_branches()` runs `traploop` with 1000 iterations. Because these loop limits are extremely small, the total benchmark runtimes last only a few milliseconds (or less). Under high load, virtualization, or coarse sampling conditions, PMU cycle sampling fails to capture enough samples inside the brief benchmark loops. This leads to false negatives where the script output lacks the expected syscall, kernel, or trap branch entries (e.g. "ERROR: Branches missing getppid[^ ]*/SYSCALL/"). Fix this by increasing the workload loop counts to 100,000 across all three test sections. Running 100,000 loops still finishes virtually instantaneously (less than 0.1 seconds), but generates enough iterations to guarantee robust branch stack capture. Fixes: b55878c90ab9 ("perf test: Add test for branch stack sampling") Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf test: Fixes for check branch stack sampling

2026-09-14T11:34:26+00:00

[ Upstream commit 86d1095fdb7017a93e9d7be875775f7e5aa5c2f5 ] When filtering branch stack samples on user events they sample in user land but may have come from the kernel. Aarch64 avoids leaking the kernel address for kaslr reasons but other platforms, for now, don't. Be more permissive in allowing kernel addresses in the source of user branch stacks. When filtering branch stack samples on kernel events they sample in kernel land but may have come from user land. Avoid the target being a user address but allow the source to be in user land. Aarch64 may not leak the user land addresses (making them 0) but other platforms do. As the kernel address sampling implies privelege, just allow this. Increase the duration of the system call sampling test to make the likelihood of sampling a system call higher (increased from 1000 to 8000 loops - a number found through experimentation on an Intel Tigerlake laptop), also make the period of the event a prime number. Put unneeded perf record output into a temporary file so that the test output isn't cluttered. More clearly state which test is running and the pass, fail or skipped result of the test. These changes make the test on an Intel tigerlake laptop reliably pass rather than reliably fail. Signed-off-by: Ian Rogers Reviewed-by: James Clark Signed-off-by: Namhyung Kim Stable-dep-of: 344d3aec164d ("perf tests: Fix flakiness in branch stack sampling tests") Signed-off-by: Sasha Levin

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

2026-09-14T11:34:26+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

2026-09-14T11:34:26+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 tests: Fix flakiness in trace record and replay test

2026-09-14T11:34:26+00:00

[ Upstream commit 509a2b9a6e142697dd5f34cdd802e5b86eababa1 ] The `perf trace record and replay` test fails intermittently on slow or virtualized hosts because the default recording workload (`sleep 1`) occasionally completes without scheduling the target `nanosleep` or `clock_nanosleep` system calls inside the recorded sample window, resulting in the error: `Failed: cannot find *nanosleep syscall`. Generalize the `perf_record_with_retry` helper in `tests/shell/lib/perf_record.sh` to support a custom record command prefix via the `PERF_RECORD_CMD` environment variable (defaulting to "perf record"). Update `trace_record_replay.sh` to use this robust retry loop running with `PERF_RECORD_CMD="perf trace record"` and a base workload of `sleep`. The test will automatically retry with scaled sleep durations (from 0.01s up to 2.0s) until the required `nanosleep` event is successfully captured. Fixes: 15bcfb96d0dd ("perf test: Add trace record and replay test") Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Signed-off-by: Sasha Levin

perf tests: Add robust record retry helper and use subsecond workloads

2026-09-14T11:34:26+00:00

[ Upstream commit 74dba58222f0d34cf8bd3eba1a6926e9654d4b6b ] Introduce `perf_record_with_retry` and `perf_record_cleanup` in a shared library `tests/shell/lib/perf_record.sh` to prevent record test failures caused by transient recording or workload delays. Update `record.sh`, `record_lbr.sh`, `pipe_test.sh`, `kvm.sh`, and `stat_all_pfm.sh` to use this robust record retry logic. These tests now start with very short durations (e.g. 0.01 seconds) and scale up if the initial recording failed to capture samples, significantly improving test execution speed on success while remaining resilient to slow systems. Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim Stable-dep-of: 509a2b9a6e14 ("perf tests: Fix flakiness in trace record and replay test") Signed-off-by: Sasha Levin