kernel/git/next/linux-next.git/tools/perf/tests, branch master

perf tests: Restore -p flag to lock contention test

2026-07-10T00:44:22+00:00

Commit ae42a2a2a3ae ("perf tests: Speed up lock contention analysis shell test") in linux-next heavily optimized the test runtimes by switching the workload from the default of 10 process groups down to 1 (`perf bench sched messaging -g 1`). However, this change inadvertently dropped the original `-p` flag, causing the benchmark to default to `socketpair()` instead of `pipe()`. While `socketpair()` still generates some lock events on x86, it fails to trigger enough samples on architectures like s390, causing the test suite to fail due to lack of captured data. Restore the omitted `-p` pipe flag. The test retains the massive speedups achieved through the `-g 1` scaling, while producing a massive density of lock events across all architectures to fully satisfy the BPF trace filtering logic. Fixes: ae42a2a2a3ae ("perf tests: Speed up lock contention analysis shell test") Signed-off-by: Ian Rogers Tested-by: Thomas Richter Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Namhyung Kim

perf stat: reject --field-separator and --json-output combination

2026-07-08T23:43:25+00:00

Specifying --field-separator option is stating you want CSV output. Passing both --field-separator and --json-output is then stating you want output to be in CSV and JSON format at same time. Currently this combination is not rejected, and the outcome is a malformed combination of CSV and JSON output. This is because of inconsistencies in various printing functions, some of them have if-else chains that start with "Should I print JSON?", and some start with "Should I print CSV?". Example of current output: $ tools/perf/perf stat -x , -j -e cpu-migrations true {"counter-value" : "0.000000", "unit" : "", "event" : "cpu-migrations", "event-runtime" : 474817, "pcnt-running" : 100.00,, Instead reject the option combination, with a helpful error message and non-zero exit code. Example of new output: $ tools/perf/perf stat -x , -j true cannot use both --field-separator and --json-output Usage: perf stat [] [] -x, --field-separator print counts with custom separator -j, --json-output print counts in JSON format Signed-off-by: Ivan Lazaric Signed-off-by: Namhyung Kim

perf tests: Add auto counter reload (ACR) sampling test

2026-07-04T16:39:04+00:00

Add auto counter reload sampling test to verify that the intended event records can be captured and the self-reloaded events won't generate any records. Signed-off-by: Dapeng Mi Signed-off-by: Namhyung Kim

perf test: Add Arm CoreSight callchain test

2026-07-03T23:52:00+00:00

Add a CoreSight shell test for synthesized callchains. The test uses the new callchain workload to generate trace and decodes it with synthesis callchain. It then verifies that the instruction samples show the expected callchain push and pop. Use control FIFOs so tracing starts only around the workload, which keeps the trace data small. The test is limited to with the cs_etm event available and root permission. After: perf test 138 -vvv 138: CoreSight synthesized callchain: ---- start ---- test child forked, pid 35581 Callchain flow matched: l1=4642868 l2=4642880 l3=4642895 l4=4642919 l5=4670494 l6=4670500 l7=4670520 ---- end(0) ---- 138: CoreSight synthesized callchain : Ok Assisted-by: Codex:GPT-5.5 Reviewed-by: James Clark Signed-off-by: Leo Yan Signed-off-by: Namhyung Kim

perf cs-etm: Filter synthesized branch samples

2026-07-03T23:51:59+00:00

The itrace 'c' and 'r' options request synthesized branch events for calls and returns only. For perf script the default itrace options are "--itrace=ce", so CS ETM should emit call branches and error events by default. CS ETM currently synthesizes a branch sample for every decoded taken branch whenever branch synthesis is enabled. This produces redundant jump and conditional branch samples. Add a branch filter derived from the itrace calls and returns options. When neither option is set, keep the existing behavior and synthesize all branch samples. When calls or returns are requested, emit only branch samples whose flags match the selected branch type, while preserving trace begin/end markers. Also update test_arm_coresight_disasm.sh and arm-cs-trace-disasm.py to use the --itrace=b option for generating branch samples. Before: perf script -F,+flags callchain_test 6114 [005] 331519.825214: 1 branches: tr strt jmp 0 [unknown] ([unknown]) => ffff8000803a3a68 perf_report_aux_output_id+0x50 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff8000803a3a74 perf_report_aux_output_id+0x5c ([kernel.kallsyms]) => ffff8000817f4d88 memset+0x0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jmp ffff8000817f4d8c memset+0x4 ([kernel.kallsyms]) => ffff8000817f4c00 __pi_memset_generic+0x0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000817f4c1c __pi_memset_generic+0x1c ([kernel.kallsyms]) => ffff8000817f4c44 __pi_memset_generic+0x44 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000817f4c4c __pi_memset_generic+0x4c ([kernel.kallsyms]) => ffff8000817f4c5c __pi_memset_generic+0x5c ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000817f4c5c __pi_memset_generic+0x5c ([kernel.kallsyms]) => ffff8000817f4cf0 __pi_memset_generic+0xf0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000817f4d30 __pi_memset_generic+0x130 ([kernel.kallsyms]) => ffff8000817f4d68 __pi_memset_generic+0x168 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000817f4d78 __pi_memset_generic+0x178 ([kernel.kallsyms]) => ffff8000817f4d6c __pi_memset_generic+0x16c ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000817f4d78 __pi_memset_generic+0x178 ([kernel.kallsyms]) => ffff8000817f4d6c __pi_memset_generic+0x16c ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000817f4d78 __pi_memset_generic+0x178 ([kernel.kallsyms]) => ffff8000817f4d6c __pi_memset_generic+0x16c ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: return ffff8000817f4d84 __pi_memset_generic+0x184 ([kernel.kallsyms]) => ffff8000803a3a78 perf_report_aux_output_id+0x60 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: jcc ffff8000803a3a98 perf_report_aux_output_id+0x80 ([kernel.kallsyms]) => ffff8000803a3b04 perf_report_aux_output_id+0xec ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff8000803a3b1c perf_report_aux_output_id+0x104 ([kernel.kallsyms]) => ffff8000803a38f8 __perf_event_header__init_id+0x0 ([kernel.kallsyms]) After: callchain_test 6114 [005] 331519.825214: 1 branches: tr strt jmp 0 [unknown] ([unknown]) => ffff8000803a3a68 perf_report_aux_output_id+0x50 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff8000803a3a74 perf_report_aux_output_id+0x5c ([kernel.kallsyms]) => ffff8000817f4d88 memset+0x0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff8000803a3b1c perf_report_aux_output_id+0x104 ([kernel.kallsyms]) => ffff8000803a38f8 __perf_event_header__init_id+0x0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff8000803a39c0 __perf_event_header__init_id+0xc8 ([kernel.kallsyms]) => ffff800080105258 __task_pid_nr_ns+0x0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff80008010528c __task_pid_nr_ns+0x34 ([kernel.kallsyms]) => ffff8000801d5610 __rcu_read_lock+0x0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff8000801052b0 __task_pid_nr_ns+0x58 ([kernel.kallsyms]) => ffff800080192078 lock_acquire+0x0 ([kernel.kallsyms]) callchain_test 6114 [005] 331519.825214: 1 branches: call ffff8000801923f4 lock_acquire+0x37c ([kernel.kallsyms]) => ffff8000801d6da0 rcu_is_watching+0x0 ([kernel.kallsyms]) Fixes: b12235b113cf ("perf tools: Add mechanic to synthesise CoreSight trace packets") Signed-off-by: Leo Yan Reviewed-by: James Clark Signed-off-by: Leo Yan Signed-off-by: Namhyung Kim

perf test: Extend perf kvm tests to check default event

2026-07-03T20:40:24+00:00

It can now pass command line arguments to perf kvm record. Let's pass 'sleep 1' directly and see it doesn't fail. $ sudo perf test -vv kvm 96: perf kvm tests: ---- start ---- test child forked, pid 3686726 Starting qemu-system-x86_64... Testing perf kvm stat Recording kvm events for pid 3686746 (duration 1s)... perf kvm stat test [Success] Testing perf kvm record/report Recording kvm profile for pid 3686746 (duration 1s)... [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.576 MB /tmp/__perf_kvm_test.perf.data.0HgX6 (4009 samples) ] perf kvm record/report test [Success] Testing perf kvm buildid-list perf kvm buildid-list test [Success] Testing perf kvm stat live perf kvm stat live test [Success] Testing perf kvm record default event with command line [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.000 MB /dev/null ] perf kvm record default event [Success] ---- end(0) ---- 96: perf kvm tests : Ok === Test Summary === Passed main tests : 1 Passed subtests : 0 Skipped tests : 0 Failed tests : 0 Tested-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tests: Include error output for skipped tests in JUnit XML

2026-07-01T00:09:14+00:00

The JUnit XML output correctly captures the stderr/stdout output of failed tests inside the element. However, for skipped tests, the output was completely discarded and the XML only received a self-closing tag. This expands the element to include the test's err_output when available, which is extremely helpful for debugging why a test was skipped (e.g. diagnosing missing prerequisites or unexpected environment states that triggered the skip) directly from CI systems parsing the XML report. Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tests: Speed up metrics checking shell tests

2026-07-01T00:09:14+00:00

Optimize the execution of the metric validation and metric listing shell test suites: 1. `stat_metrics_values.sh`: The Python metric validator runs the `perf bench futex hash` workload for each validated metric relationship. Reduce the benchmark runtime limit from `-r 2` (2 seconds) to `-r 1` (1 second). This cuts the workload duration in half while still generating sufficient PMU events to satisfy non-zero threshold metric validations. 2. `stat_all_metrics.sh`: The metric checking test runs `perf stat` sequentially across all 433+ listed metrics. Change the default workload for system-wide runs from `sleep 0.01` to `true`. This avoids the 10ms sleep delay on each sequential metric invocation, saving over 4 seconds of total wall time during full test suite runs. Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tests: Speed up lock contention analysis shell test

2026-07-01T00:09:14+00:00

The lock contention analysis test suite (`lock_contention.sh`) performs a series of 13 separate profiling checks to verify various aggregation and filtering parameters of `perf lock contention`. Each of these checks runs the `perf bench sched messaging` messaging benchmark as its workload. By default, `sched messaging` runs 10 groups of 40 processes (400 processes total) generating substantial task scheduling, context switching, and IPC message passing. When traced system-wide for lock events, the tracing overhead (handling millions of lock acquisitions and releases) slows execution down significantly, causing the test suite to take over 80 seconds. Optimize this by introducing a scaled-down messaging benchmark workload: `perf bench sched messaging -g 1 -p`. Running 1 group (40 processes) takes only 0.01 seconds natively (instead of 0.08 seconds), drastically reduces the sheer volume of lock acquire/release trace events, and reduces CPU context switching during tracing while still generating sufficient lock events to fully exercise the BPF/record filters. Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim

perf tests: Speed up off-cpu profiling tests

2026-07-01T00:09:14+00:00

The off-cpu profiling test suite runs multiple recording commands with a default workload of `sleep 1` to test the off-cpu threshold configurations (specifically, above 999ms and below 1200ms). This adds a mandatory 3.0 seconds of sleep overhead. Optimize this by scaling down the thresholds and workload durations by a factor of 10: - Use `sleep 0.1` as the workload duration. - Change the above-threshold test to use `--off-cpu-thresh 50` and `sleep 0.1`. - Change the below-threshold test to use `--off-cpu-thresh 500` and `sleep 0.1`. - Update the awk period check in the above-threshold test to look for a period greater than 50,000,000 ns (50ms) instead of 999,000,000 ns (999ms). This reduces raw test sleep overhead from 3.0s down to 0.3s, yielding a ~2.7 second speedup for this test. Assisted-by: Antigravity:gemini-3.1-pro Signed-off-by: Ian Rogers Signed-off-by: Namhyung Kim