kernel/git/stable/linux.git/tools/perf/Documentation, branch linux-6.14.y

perf tools: Fix up some comments and code to properly use the event_source bus

2025-04-07T08:11:12+00:00

commit 0cced76a0276610e86e8b187c09f0e9ef85b9299 upstream. In sysfs, the perf events are all located in /sys/bus/event_source/devices/ but some places ended up hard-coding the location to be at the root of /sys/devices/ which could be very risky as you do not exactly know what type of device you are accessing in sysfs at that location. So fix this all up by properly pointing everything at the bus device list instead of the root of the sysfs devices/ tree. Cc: stable Signed-off-by: Greg Kroah-Hartman Reviewed-by: Kan Liang Link: https://lore.kernel.org/r/2025021955-implant-excavator-179d@gregkh Signed-off-by: Namhyung Kim Signed-off-by: Greg Kroah-Hartman

Merge tag 'perf-tools-for-v6.14-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools

2025-01-24T13:45:40+00:00

Pull perf-tools updates from Namhyung Kim: "There are a lot of changes in the perf tools in this cycle. build: - Use generic syscall table to generate syscall numbers on supported archs - This also enables to get rid of libaudit which was used for syscall numbers - Remove python2 support as it's deprecated for years - Fix issues on static build with libzstd perf record: - Intel-PT supports "aux-action" config term to pause or resume tracing in the aux-buffer. Users can start the intel_pt event as "started-paused" and configure other events to control the Intel-PT tracing: # perf record --kcore -e intel_pt/aux-action=start-paused/ \ -e syscalls:sys_enter_newuname/aux-action=resume/ \ -e syscalls:sys_exit_newuname/aux-action=pause/ -- uname This requires kernel support (which was added in v6.13) perf lock: - 'perf lock contention' command has an ability to symbolize locks in dynamically allocated objects using slab cache name when it runs with BPF. Those dynamic locks would have "&" prefix in the name to distinguish them from ordinary (static) locks # perf lock con -abl -E 5 sleep 1 contended total wait max wait avg wait address symbol 2 1.95 us 1.77 us 975 ns ffff9d5e852d3498 &task_struct (mutex) 1 1.18 us 1.18 us 1.18 us ffff9d5e852d3538 &task_struct (mutex) 4 1.12 us 354 ns 279 ns ffff9d5e841ca800 &kmalloc-cg-512 (mutex) 2 859 ns 617 ns 429 ns ffffffffa41c3620 delayed_uprobe_lock (mutex) 3 691 ns 388 ns 230 ns ffffffffa41c0940 pack_mutex (mutex) This also requires kernel/BPF support (which was added in v6.13) perf ftrace: - 'perf ftrace latency' command gets a couple of options to support linear buckets instead of exponential. Also it's possible to specify max and min latency for the linear buckets: # perf ftrace latency -abn -T switch_mm_irqs_off --bucket-range=100 \ --min-latency=200 --max-latency=800 -- sleep 1 # DURATION | COUNT | GRAPH | 0 - 200 ns | 186 | ### | 200 - 300 ns | 256 | ##### | 300 - 400 ns | 364 | ####### | 400 - 500 ns | 223 | #### | 500 - 600 ns | 111 | ## | 600 - 700 ns | 41 | | 700 - 800 ns | 141 | ## | 800 - ... ns | 169 | ### | # statistics (in nsec) total time: 2162212 avg time: 967 max time: 16817 min time: 132 count: 2236 - As you can see in the above example, it nows shows the statistics at the end so that users can see the avg/max/min latencies easily - 'perf ftrace profile' command has --graph-opts option like 'perf ftrace trace' so that it can control the tracing behaviors in the same way. For example, it can limit the function call depth or threshold perf script: - Improve physical memory resolution in 'mem-phys-addr' script by parsing /proc/iomem file # perf script mem-phys-addr -- find / ... Event: mem_inst_retired.all_loads:P Memory type count percentage ---------------------------------------- ---------- ---------- 100000000-85f7fffff : System RAM 8929 69.7 547600000-54785d23f : Kernel data 1240 9.7 546a00000-5474bdfff : Kernel rodata 490 3.8 5480ce000-5485fffff : Kernel bss 121 0.9 0-fff : Reserved 3860 30.1 100000-89c01fff : System RAM 18 0.1 8a22c000-8df6efff : System RAM 5 0.0 Others: - 'perf test' gets --runs-per-test option to run the test cases repeatedly. This would be helpful to see if it's flaky - Add 'parse_events' method to Python perf extension module, so that users can use the same event parsing logic in the python code. One more step towards implementing perf tools in Python. :) - Support opening tracepoint events without libtraceevent. This will be helpful if it won't use the tracing data like in 'perf stat' - Update ARM Neoverse N2/V2 JSON events and metrics" * tag 'perf-tools-for-v6.14-2025-01-21' of git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools: (176 commits) perf test: Update event_groups test to use instructions perf bench: Fix undefined behavior in cmpworker() perf annotate: Prefer passing evsel to evsel->core.idx perf lock: Rename fields in lock_type_table perf lock: Add percpu-rwsem for type filter perf lock: Fix parse_lock_type which only retrieve one lock flag perf lock: Fix return code for functions in __cmd_contention perf hist: Fix width calculation in hpp__fmt() perf hist: Fix bogus profiles when filters are enabled perf hist: Deduplicate cmp/sort/collapse code perf test: Improve verbose documentation perf test: Add a runs-per-test flag perf test: Fix parallel/sequential option documentation perf test: Send list output to stdout rather than stderr perf test: Rename functions and variables for better clarity perf tools: Expose quiet/verbose variables in Makefile.perf perf config: Add a function to set one variable in .perfconfig perf test perftool_testsuite: Return correct value for skipping perf test perftool_testsuite: Add missing description perf test record+probe_libc_inet_pton: Make test resilient ...

perf lock: Add percpu-rwsem for type filter

2025-01-17T18:12:40+00:00

percpu-rwsem was missing in man page. And for backward compatibility, replace `pcpu-sem` with `percpu-rwsem` before parsing lock name. Tested `./perf lock con -ab -Y pcpu-sem` and `./perf lock con -ab -Y percpu-rwsem` Fixes: 4f701063bfa2 ("perf lock contention: Show lock type with address") Reviewed-by: Namhyung Kim Signed-off-by: Chun-Tse Shao Cc: nick.forrington@arm.com Link: https://lore.kernel.org/r/20250116235838.2769691-2-ctshao@google.com Signed-off-by: Namhyung Kim

perf test: Improve verbose documentation

2025-01-16T19:01:03+00:00

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

2025-01-16T19:01:03+00:00

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

2025-01-16T19:01:03+00:00

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 docs: arm_spe: Document new discard mode

2025-01-10T14:50:55+00:00

Document the flag along with PMU events to hint what it's used for and give an example with other useful options to get minimal output. Reviewed-by: Yeoreum Yun Signed-off-by: James Clark Link: https://lore.kernel.org/r/20250108142904.401139-3-james.clark@linaro.org Signed-off-by: Will Deacon

perf tools: Remove dependency on libaudit

2025-01-10T13:59:42+00:00

All architectures now support HAVE_SYSCALL_TABLE_SUPPORT, so the flag is no longer needed. With the removal of the flag, the related GENERIC_SYSCALL_TABLE can also be removed. libaudit was only used as a fallback for when HAVE_SYSCALL_TABLE_SUPPORT was not defined, so libaudit is also no longer needed for any architecture. Signed-off-by: Charlie Jenkins Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Arnd Bergmann Cc: Christian Brauner Cc: Guo Ren Cc: Günther Noack Cc: Ian Rogers Cc: Ingo Molnar Cc: James Clark Cc: Jiri Olsa Cc: John Garry Cc: Jonathan Corbet Cc: Leo Yan Cc: Mark Rutland Cc: Mickaël Salaün Cc: Mike Leach Cc: Namhyung Kim Cc: Palmer Dabbelt Cc: Paul Walmsley Cc: Peter Zijlstra Cc: Will Deacon Link: https://lore.kernel.org/r/20250108-perf_syscalltbl-v6-16-7543b5293098@rivosinc.com Signed-off-by: Arnaldo Carvalho de Melo

perf ftrace profile: Add --graph-opts option

2025-01-08T20:20:42+00:00

Like trace subcommand, it should be able to pass some options to control the tracing behavior for the function graph tracer. But some options are limited in order to maintain the internal behavior. For example, it can limit the function call depth like below: # perf ftrace profile --graph-opts depth=5 -- myprog Committer testing: root@number:~# perf ftrace profile --graph-opts thresh=1000 -- sleep 1 # Total (us) Avg (us) Max (us) Count Function 1001419.301 500709.650 1000032.000 2 x64_sys_call 1000032.000 1000032.000 1000032.000 1 __x64_sys_clock_nanosleep 1000032.000 1000032.000 1000032.000 1 common_nsleep 1000031.000 1000031.000 1000031.000 1 do_nanosleep 1000031.000 1000031.000 1000031.000 1 hrtimer_nanosleep 1000024.000 1000024.000 1000024.000 1 schedule 1387.208 1387.208 1387.208 1 __x64_sys_execve 1386.691 1386.691 1386.691 1 do_execveat_common.isra.0 1334.170 1334.170 1334.170 1 bprm_execve 1258.413 1258.413 1258.413 1 load_elf_binary 1123.068 1123.068 1123.068 1 begin_new_exec 1113.550 1113.550 1113.550 1 mmput 1109.237 1109.237 1109.237 1 exit_mmap root@number:~# perf ftrace profile --graph-opts thresh=1200 -- sleep 1 # Total (us) Avg (us) Max (us) Count Function 1001448.204 500724.102 1000018.000 2 x64_sys_call 1000017.000 1000017.000 1000017.000 1 __x64_sys_clock_nanosleep 1000017.000 1000017.000 1000017.000 1 common_nsleep 1000017.000 1000017.000 1000017.000 1 hrtimer_nanosleep 1000016.000 1000016.000 1000016.000 1 do_nanosleep 1000012.000 1000012.000 1000012.000 1 schedule 1430.112 1430.112 1430.112 1 __x64_sys_execve 1429.581 1429.581 1429.581 1 do_execveat_common.isra.0 1376.289 1376.289 1376.289 1 bprm_execve 1301.743 1301.743 1301.743 1 load_elf_binary root@number:~# Reviewed-by: James Clark Signed-off-by: Namhyung Kim Tested-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Kan Liang Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20250107224352.1128669-2-namhyung@kernel.org Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Add documentation for --force-btf option

2024-12-26T15:19:26+00:00

The --force-btf option is intended for debugging purposes and is currently undocumented. Add documentation for it. Committer notes: We need a follow up patch expanding on what can be done via BTF and what isn't possible and thus needs further work to convert kernel C source code into tables that can then be associated with syscall integer args and struct members, as discussed in: https://lore.kernel.org/all/20241215190712.787847-3-howardchu95@gmail.com/T/#mcfbba653200775c59c730705229a49b34a153db7 Signed-off-by: Howard Chu Acked-by: Namhyung Kim Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ian Rogers Cc: Jiri Olsa Cc: Kan Liang Cc: Mark Rutland Link: https://lore.kernel.org/r/20241215190712.787847-3-howardchu95@gmail.com Link: https://lore.kernel.org/all/20241215190712.787847-3-howardchu95@gmail.com/T/#mcfbba653200775c59c730705229a49b34a153db7 Signed-off-by: Arnaldo Carvalho de Melo