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

perf doc: Add AMD IBS usage document

2024-06-20T23:51:55Z

Add a perf man page document that describes how to exploit AMD IBS with Linux perf. Brief intro about IBS and simple one-liner examples will help naive users to get started. This is not meant to be an exhaustive IBS guide. User should refer latest AMD64 Architecture Programmer's Manual for detailed description of IBS. Usage: $ man perf-amd-ibs Signed-off-by: Ravi Bangoria Reviewed-by: Arnaldo Carvalho de Melo Cc: ananth.narayan@amd.com Cc: sandipan.das@amd.com Cc: santosh.shukla@amd.com Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240620054104.815-1-ravi.bangoria@amd.com

perf tools: Make it possible to see perf's kernel and module memory mappings

2024-02-08T23:49:39Z

Dump kmaps if using 'perf --debug kmaps' or verbose > 2 (e.g. -vvv) for tools 'perf script' and 'perf report' if there is no browser. Example: $ perf --debug kmaps script 2>&1 >/dev/null | grep kvm.intel build id event received for /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko: 0691d75e10e72ebbbd45a44c59f6d00a5604badf [20] Map: 0-3a3 4f5d8 [kvm_intel].modinfo Map: 0-5240 5f280 [kvm_intel]__versions Map: 0-30 64 [kvm_intel].note.Linux Map: 0-14 644c0 [kvm_intel].orc_header Map: 0-5297 43680 [kvm_intel].rodata Map: 0-5bee 3b837 [kvm_intel].text.unlikely Map: 0-7e0 41430 [kvm_intel].noinstr.text Map: 0-2080 713c0 [kvm_intel].bss Map: 0-26 705c8 [kvm_intel].data..read_mostly Map: 0-5888 6a4c0 [kvm_intel].data Map: 0-22 70220 [kvm_intel].data.once Map: 0-40 705f0 [kvm_intel].data..percpu Map: 0-1685 41d20 [kvm_intel].init.text Map: 0-4b8 6fd60 [kvm_intel].init.data Map: 0-380 70248 [kvm_intel]__dyndbg Map: 0-8 70218 [kvm_intel].exit.data Map: 0-438 4f980 [kvm_intel]__param Map: 0-5f5 4ca0f [kvm_intel].rodata.str1.1 Map: 0-3657 493b8 [kvm_intel].rodata.str1.8 Map: 0-e0 70640 [kvm_intel].data..ro_after_init Map: 0-500 70ec0 [kvm_intel].gnu.linkonce.this_module Map: ffffffffc13a7000-ffffffffc1421000 a0 /lib/modules/6.7.2-local/kernel/arch/x86/kvm/kvm-intel.ko The example above shows how the module section mappings are all wrong except for the main .text mapping at 0xffffffffc13a7000. Signed-off-by: Adrian Hunter Acked-by: Namhyung Kim Cc: Like Xu Signed-off-by: Namhyung Kim Link: https://lore.kernel.org/r/20240208085326.13432-2-adrian.hunter@intel.com

perf tools: Add --debug-file option to redirect debug output

2023-11-28T17:14:53Z

Currently, debug messages is output to stderr, add --debug-file option to support redirection to a specified file. Some test scenarios: # perf --list-opts --help --version --exec-path --html-path --paginate --no-pager --debugfs-dir --buildid-dir --list-cmds --list-opts --debug --debug-file # perf --debug-file No path given for --debug-file. Usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS] # perf --debug-file /sys/perf.log record -v true Open debug file '/sys/perf.log' failed: Permission denied Usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS] # perf --debug-file /tmp/perf.log record -v true [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.013 MB perf.data (26 samples) ] # cat /tmp/perf.log DEBUGINFOD_URLS= Using CPUID GenuineIntel-6-3E-4 nr_cblocks: 0 affinity: SYS mmap flush: 1 comp level: 0 mmap size 528384B Control descriptor is not initialized mmap size 528384B Looking at the vmlinux_path (8 entries long) Using /proc/kcore for kernel data Using /proc/kallsyms for symbols symbol:unmap_start file:(null) line:0 offset:0 return:0 lazy:(null) symbol:unmap_complete file:(null) line:0 offset:0 return:0 lazy:(null) symbol:map_start file:(null) line:0 offset:0 return:0 lazy:(null) symbol:map_complete file:(null) line:0 offset:0 return:0 lazy:(null) symbol:reloc_start file:(null) line:0 offset:0 return:0 lazy:(null) symbol:reloc_complete file:(null) line:0 offset:0 return:0 lazy:(null) symbol:init_start file:(null) line:0 offset:0 return:0 lazy:(null) symbol:init_complete file:(null) line:0 offset:0 return:0 lazy:(null) symbol:lll_lock_wait_private file:(null) line:0 offset:0 return:0 lazy:(null) symbol:lll_lock_wait file:(null) line:0 offset:0 return:0 lazy:(null) symbol:setjmp file:(null) line:0 offset:0 return:0 lazy:(null) symbol:longjmp file:(null) line:0 offset:0 return:0 lazy:(null) symbol:longjmp_target file:(null) line:0 offset:0 return:0 lazy:(null) failed to write feature HYBRID_TOPOLOGY Signed-off-by: Yang Jihong Acked-by: Arnaldo Carvalho de Melo Cc: Adrian Hunter Cc: Alexander Shishkin Cc: Ian Rogers Cc: Ingo Molnar Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: https://lore.kernel.org/r/20231031105523.1472558-1-yangjihong1@huawei.com Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Add man page entry for Arm SPE

2022-04-14T11:54:03Z

The SPE integration in Perf has quite a few usability quirks that can't be found by just reading the reference manual. So document this and at the same time add a summary of the feature that is also hard to find elsewhere. Reviewed-by: Leo Yan Signed-off-by: James Clark Co-authored-by: Al Grant Co-authored-by: Luke Dare Cc: Alexander Shishkin Cc: German Gomez Cc: Jiri Olsa Cc: Leo Yan Cc: Mark Rutland Cc: Namhyung Kim Link: https://lore.kernel.org/r/20220413084021.2556142-1-james.clark@arm.com Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Add perf-iostat link to manpages

2022-04-09T17:20:59Z

Signed-off-by: Michael Petlan Acked-by: Ian Rogers Cc: Jiri Olsa Link: https://lore.kernel.org/r/20220404221541.30312-1-mpetlan@redhat.com Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Add man pages to see also

2021-03-02T12:37:38Z

Add all other man pages to the "see also" list except for perf-script-perl and perf-script-python that are linked to from perf-script. Signed-off-by: Ian Rogers Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Mark Rutland Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lore.kernel.org/lkml/20201120063037.3166069-1-irogers@google.com Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Improve help information in perf.txt

2020-09-17T19:03:31Z

perf has many undocumented options, such as:-vv, --exec-path, --html-path, -p, --paginate,--no-pager, --debugfs-dir, --buildid-dir, --list-cmds, --list-opts. Add entris for these options in perf.txt. Signed-off-by: Zejiang Tang Acked-by: Namhyung Kim Cc: Alexander Shishkin Cc: Jiri Olsa Cc: Mark Rutland Cc: Peter Zijlstra Cc: Ravi Bangoria Link: http://lore.kernel.org/lkml/1599645194-8438-1-git-send-email-tangzejiang@loongson.cn Signed-off-by: Arnaldo Carvalho de Melo

perf tool: Provide an option to print perf_event_open args and return value

2019-11-12T11:32:27Z

Perf record with verbose=2 already prints this information along with whole lot of other traces which requires lot of scrolling. Introduce an option to print only perf_event_open() arguments and return value. Sample o/p: $ perf --debug perf-event-open=1 record -- ls > /dev/null ------------------------------------------------------------ perf_event_attr: size 112 { sample_period, sample_freq } 4000 sample_type IP|TID|TIME|PERIOD read_format ID disabled 1 inherit 1 exclude_kernel 1 mmap 1 comm 1 freq 1 enable_on_exec 1 task 1 precise_ip 3 sample_id_all 1 exclude_guest 1 mmap2 1 comm_exec 1 ksymbol 1 bpf_event 1 ------------------------------------------------------------ sys_perf_event_open: pid 4308 cpu 0 group_fd -1 flags 0x8 = 4 sys_perf_event_open: pid 4308 cpu 1 group_fd -1 flags 0x8 = 5 sys_perf_event_open: pid 4308 cpu 2 group_fd -1 flags 0x8 = 6 sys_perf_event_open: pid 4308 cpu 3 group_fd -1 flags 0x8 = 8 sys_perf_event_open: pid 4308 cpu 4 group_fd -1 flags 0x8 = 9 sys_perf_event_open: pid 4308 cpu 5 group_fd -1 flags 0x8 = 10 sys_perf_event_open: pid 4308 cpu 6 group_fd -1 flags 0x8 = 11 sys_perf_event_open: pid 4308 cpu 7 group_fd -1 flags 0x8 = 12 ------------------------------------------------------------ perf_event_attr: type 1 size 112 config 0x9 watermark 1 sample_id_all 1 bpf_event 1 { wakeup_events, wakeup_watermark } 1 ------------------------------------------------------------ sys_perf_event_open: pid -1 cpu 0 group_fd -1 flags 0x8 sys_perf_event_open failed, error -13 [ perf record: Woken up 1 times to write data ] [ perf record: Captured and wrote 0.002 MB perf.data (9 samples) ] Committer notes: Just like the 'verbose' variable this new 'debug_peo_args' needs to be added to util/python.c, since we don't link the debug.o file in the python binding, which ended up making 'perf test python' fail with: # perf test -v python 18: 'import perf' in python : --- start --- test child forked, pid 19237 Traceback (most recent call last): File "", line 1, in ImportError: /tmp/build/perf/python/perf.so: undefined symbol: debug_peo_args test child finished with -1 ---- end ---- 'import perf' in python: FAILED! # After adding that new variable to util/python.c: # perf test -v python 18: 'import perf' in python : --- start --- test child forked, pid 22364 test child finished with 0 ---- end ---- 'import perf' in python: Ok # Signed-off-by: Ravi Bangoria Tested-by: Arnaldo Carvalho de Melo Acked-by: Jiri Olsa Link: http://lore.kernel.org/lkml/20191108094128.28769-1-ravi.bangoria@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf docs: Add description for stderr

2019-05-16T17:17:24Z

'perf report' displays recorded data on the screen and emits warnings and debug messages in the status line (last one on screen). perf also supports the possibility to write all debug messages to stderr (instead of writing them to the status line). This is achieved with the following command: # ./perf --debug stderr=1 report -vvvvv -i ~/fast.data 2>/tmp/2 # ll /tmp/2 -rw-rw-r-- 1 tmricht tmricht 5420835 May 7 13:46 /tmp/2 # The usage of variable stderr=1 is not documented, so add it to the perf man page. Signed-off-by: Thomas Richter Cc: Heiko Carstens Cc: Hendrik Brueckner Cc: Martin Schwidefsky Link: http://lkml.kernel.org/r/20190513080220.91966-1-tmricht@linux.ibm.com Signed-off-by: Arnaldo Carvalho de Melo

perf tools: Handle -h and -v options

2015-10-05T19:36:18Z

Adding handling for '-h' and '-v' options to invoke help and version command respectively. Current behaviour is: $ perf -v Unknown option: -v Usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS] $ perf -h Unknown option: -h Usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS] New behaviour: $ perf -h usage: perf [--version] [--help] [OPTIONS] COMMAND [ARGS] The most commonly used perf commands are: annotate Read perf.data (created by perf record) and display annotated code archive Create archive with object files with build-ids found in perf.data file bench General framework for benchmark suites ... $ perf -v perf version 4.3.rc3.gc99e32 Updated man page. Requested-by: Peter Zijlstra Signed-off-by: Jiri Olsa Tested-by: Arnaldo Carvalho de Melo Cc: David Ahern Cc: Don Zickus Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/1444068369-20978-10-git-send-email-jolsa@kernel.org Signed-off-by: Arnaldo Carvalho de Melo