kernel/tools/perf/Documentation/perf-test.txt, branch linux-rolling-stable

perf test: Improve verbose documentation

2025-01-16T19:01:03Z

Add a little more detail on the output expectations for each verbose level. Signed-off-by: Ian Rogers Reviewed-by: Namhyung Kim Cc: James Clark Link: https://lore.kernel.org/r/20250110045736.598281-6-irogers@google.com Signed-off-by: Namhyung Kim

perf test: Add a runs-per-test flag

2025-01-16T19:01:03Z

To detect flakes it is useful to run tests more than once. Add a runs-per-test flag that will run each test multiple times. Example output: ``` $ perf test -r 3 lbr -v 122: perf record LBR tests : Ok 122: perf record LBR tests : Ok 122: perf record LBR tests : Ok ``` Update the documentation for the runs-per-test option. Signed-off-by: Ian Rogers Reviewed-by: Namhyung Kim Cc: James Clark Link: https://lore.kernel.org/r/20250110045736.598281-5-irogers@google.com Signed-off-by: Namhyung Kim

perf test: Fix parallel/sequential option documentation

2025-01-16T19:01:03Z

The parallel option was removed in commit 94d1a913bdc4 ("perf test: Make parallel testing the default"). Update the sequential documentation to reflect it isn't the default except for "exclusive" tests. Fixes: 94d1a913bdc4 ("perf test: Make parallel testing the default") Signed-off-by: Ian Rogers Reviewed-by: Namhyung Kim Cc: James Clark Link: https://lore.kernel.org/r/20250110045736.598281-4-irogers@google.com Signed-off-by: Namhyung Kim

perf test: Document the -w/--workload option

2024-10-22T04:10:50Z

Wasn't documented so far, mention that it is mostly used in the shell regression tests. Signed-off-by: Arnaldo Carvalho de Melo Reviewed-by: James Clark Cc: Thomas Gleixner Cc: Clark Williams Link: https://lore.kernel.org/r/20241020021842.1752770-4-acme@kernel.org Signed-off-by: Namhyung Kim

perf test: Reintroduce -p/--parallel and make -S/--sequential the default

2024-04-27T01:28:08Z

We can't default to doing parallel tests as there are tests that compete for the same resources and thus clash, for instance tests that put in place 'perf probe' probes, that clean the probes without regard to other tests needs, ARM64 coresight tests, Intel PT ones, etc. So reintroduce --p/--parallel and make -S/--sequential the default. We need to come up with infrastructure that state which tests can't run in parallel because they need exclusive access to some resource, something as simple as "probes" that would then avoid 'perf probe' tests from running while other such test is running, or make the tests more resilient, till then we can't use parallel mode as default. While at it, document all these options in the 'perf test' man page. Reported-by: Adrian Hunter Reported-by: Arnaldo Carvalho de Melo Reported-by: James Clark Reviewed-by: Ian Rogers Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Link: https://lore.kernel.org/lkml/Ziwm18BqIn_vc1vn@x1 Signed-off-by: Arnaldo Carvalho de Melo

perf test: Add Symbols test

2023-01-22T21:09:56Z

Add a test to check function symbols do not overlap and are not zero length. The main motivation for the test is to make it easier to review changes to PLT symbol synthesis i.e. changes to dso__synthesize_plt_symbols(). By default the test uses the perf executable as a test DSO, but a specific DSO can be specified via a new perf test option "--dso". The test is useful in the following ways: - Any DSO can be tested, even ones that do not run on the current architecture. For example, using cross-compiled DSOs to see how well perf handles different architectures. - With verbose > 1 (e.g. -vv), all the symbols are printed, which makes it easier to see issues. - perf removes duplicate symbols and expands zero-length symbols to reach the next symbol, however that is done before adding synthesized symbols, so the test is checking those also. Example: $ perf test -v Symbols 74: Symbols : --- start --- test child forked, pid 154918 Testing /home/user/bin/perf Overlapping symbols: 7d000-7f3a0 g _init 7d030-7d040 g __printf_chk@plt test child finished with -1 ---- end ---- Symbols: FAILED! Note the test fails because perf expands the _init symbol over the PLT because there are no PLT symbols at that point, but then dso__synthesize_plt_symbols() creates them. Signed-off-by: Adrian Hunter Tested-by: Arnaldo Carvalho de Melo Acked-by: Ian Rogers Cc: Jiri Olsa Cc: Namhyung Kim Link: https://lore.kernel.org/r/20230120123456.12449-2-adrian.hunter@intel.com Signed-off-by: Arnaldo Carvalho de Melo

perf test: Add -F/--dont-fork option

2016-06-30T21:27:45Z

Adding -F/--dont-fork option to bypass forking for each test. It's useful for debugging test. Signed-off-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Tested-by: Nilay Vaish Cc: David Ahern Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1467113345-12669-1-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf Documentation: Fix typos in perf/Documentation

2014-10-15T20:39:02Z

This patch fix spelling typos found in tool/perf/Documentation. Signed-off-by: Masanari Iida Acked-by: Randy Dunlap Cc: Ingo Molnar Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Randy Dunlap Link: http://lkml.kernel.org/r/1410275930-17207-1-git-send-email-standby24x7@gmail.com Signed-off-by: Arnaldo Carvalho de Melo

perf test: Allow skipping tests

2013-01-24T19:40:53Z

Sometimes a test is problematic for some reason and one wants to skip it, for instance: [root@sandy ~]# perf test 1: vmlinux symtab matches kallsyms : Ok 2: detect open syscall event : Ok 3: detect open syscall event on all cpus : Ok 4: read samples using the mmap interface : Ok 5: parse events tests : Warning: bad op token { Warning: bad op token { Warning: bad op token { Warning: bad op token { Warning: bad op token { Warning: function is_writable_pte not defined Segmentation fault (core dumped) So now we can use -s/--skip while the problematic tests are being fixed, allowing us to test all the other entries: [root@sandy ~]# perf test -s 5 1: vmlinux symtab matches kallsyms : Ok 2: detect open syscall event : Ok 3: detect open syscall event on all cpus : Ok 4: read samples using the mmap interface : Ok 5: parse events tests : Skip (user override) 6: x86 rdpmc test : Ok 7: Validate PERF_RECORD_* events & perf_sample fields : Ok 8: Test perf pmu format parsing : Ok 9: Test dso data interface : Ok 10: roundtrip evsel->name check : Ok 11: Check parsing of sched tracepoints fields : Ok 12: Generate and check syscalls:sys_enter_open event fields: Ok 13: struct perf_event_attr setup : Ok 14: Test matching and linking mutliple hists : Ok 15: Try 'use perf' in python, checking link problems : Ok [root@sandy ~]# Cc: David Ahern Cc: Frederic Weisbecker Cc: Jiri Olsa Cc: Mike Galbraith Cc: Namhyung Kim Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-klzd8p57jzdryafqkmlppcb1@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf test: Allow running just a subset of the available tests

2011-11-29T16:04:35Z

To obtain a list of available tests: [root@emilia linux]# perf test list 1: vmlinux symtab matches kallsyms 2: detect open syscall event 3: detect open syscall event on all cpus 4: read samples using the mmap interface 5: parse events tests [root@emilia linux]# To list just a subset: [root@emilia linux]# perf test list syscall 2: detect open syscall event 3: detect open syscall event on all cpus [root@emilia linux]# To run a subset: [root@emilia linux]# perf test detect 2: detect open syscall event: Ok 3: detect open syscall event on all cpus: Ok [root@emilia linux]# Specific tests can be chosen by number: [root@emilia linux]# perf test 1 3 parse 1: vmlinux symtab matches kallsyms: Ok 3: detect open syscall event on all cpus: Ok 5: parse events tests: Ok [root@emilia linux]# Now to write more tests! Suggested-by: Peter Zijlstra Cc: David Ahern Cc: Frederic Weisbecker Cc: Mike Galbraith Cc: Paul Mackerras Cc: Peter Zijlstra Cc: Stephane Eranian Link: http://lkml.kernel.org/n/tip-nqec2145qfxdgimux28aw7v8@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo