kernel/linux.git/Documentation/trace/histogram.rst, branch v6.12.91

tracing: Rename stacktrace field to common_stacktrace

2023-05-24T03:38:23+00:00

The histogram and synthetic events can use a pseudo event called "stacktrace" that will create a stacktrace at the time of the event and use it just like it was a normal field. We have other pseudo events such as "common_cpu" and "common_timestamp". To stay consistent with that, convert "stacktrace" to "common_stacktrace". As this was used in older kernels, to keep backward compatibility, this will act just like "common_cpu" did with "cpu". That is, "cpu" will be the same as "common_cpu" unless the event has a "cpu" field. In which case, the event's field is used. The same is true with "stacktrace". Also update the documentation to reflect this change. Link: https://lore.kernel.org/linux-trace-kernel/20230523230913.6860e28d@rorschach.local.home Cc: Masami Hiramatsu Cc: Tom Zanussi Cc: Mark Rutland Signed-off-by: Steven Rostedt (Google)

Merge tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace

2023-02-23T18:20:49+00:00

Pull tracing updates from Steven Rostedt: - Add function names as a way to filter function addresses - Add sample module to test ftrace ops and dynamic trampolines - Allow stack traces to be passed from beginning event to end event for synthetic events. This will allow seeing the stack trace of when a task is scheduled out and recorded when it gets scheduled back in. - Add trace event helper __get_buf() to use as a temporary buffer when printing out trace event output. - Add kernel command line to create trace instances on boot up. - Add enabling of events to instances created at boot up. - Add trace_array_puts() to write into instances. - Allow boot instances to take a snapshot at the end of boot up. - Allow live patch modules to include trace events - Minor fixes and clean ups * tag 'trace-v6.3' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (31 commits) tracing: Remove unnecessary NULL assignment tracepoint: Allow livepatch module add trace event tracing: Always use canonical ftrace path tracing/histogram: Fix stacktrace histogram Documententation tracing/histogram: Fix stacktrace key tracing/histogram: Fix a few problems with stacktrace variable printing tracing: Add BUILD_BUG() to make sure stacktrace fits in strings tracing/histogram: Don't use strlen to find length of stacktrace variables tracing: Allow boot instances to have snapshot buffers tracing: Add trace_array_puts() to write into instance tracing: Add enabling of events to boot instances tracing: Add creation of instances at boot command line tracing: Fix trace_event_raw_event_synth() if else statement samples: ftrace: Make some global variables static ftrace: sample: avoid open-coded 64-bit division samples: ftrace: Include the nospec-branch.h only for x86 tracing: Acquire buffer from temparary trace sequence tracing/histogram: Wrap remaining shell snippets in code blocks tracing/osnoise: No need for schedule_hrtimeout range bpf/tracing: Use stage6 of tracing to not duplicate macros ...

tracing/histogram: Fix stacktrace histogram Documententation

2023-02-16T18:49:39+00:00

Fix a small problem with the histogram specification in the Documentation, and change the example to show output using a stacktrace field rather than the global stacktrace. Link: https://lkml.kernel.org/r/f75f807dd4998249e513515f703a2ff7407605f4.1676063532.git.zanussi@kernel.org Signed-off-by: Tom Zanussi Signed-off-by: Steven Rostedt (Google)

tracing/histogram: Wrap remaining shell snippets in code blocks

2023-02-07T17:41:11+00:00

Most shell command snippets (echo/cat) and their output are already in literal code blocks. However a few still isn't wrapped, in which the htmldocs output is ugly. Wrap the remaining unwrapped snippets, while also fix recent kernel test robot warnings. Link: https://lore.kernel.org/linux-trace-kernel/20230129031402.47420-1-bagasdotme@gmail.com Cc: Masami Hiramatsu Cc: Jonathan Corbet Link: https://lore.kernel.org/linux-doc/202301290253.LU5yIxcJ-lkp@intel.com/ Fixes: 88238513bb2671 ("tracing/histogram: Document variable stacktrace") Reported-by: kernel test robot Signed-off-by: Bagas Sanjaya Signed-off-by: Steven Rostedt (Google)

docs: ftrace: always use canonical ftrace path

2023-01-31T21:02:30+00:00

The canonical location for the tracefs filesystem is at /sys/kernel/tracing. But, from Documentation/trace/ftrace.rst: Before 4.1, all ftrace tracing control files were within the debugfs file system, which is typically located at /sys/kernel/debug/tracing. For backward compatibility, when mounting the debugfs file system, the tracefs file system will be automatically mounted at: /sys/kernel/debug/tracing Many parts of Documentation still reference this older debugfs path, so let's update them to avoid confusion. Signed-off-by: Ross Zwisler Reviewed-by: Steven Rostedt (Google) Link: https://lore.kernel.org/r/20230125213251.2013791-1-zwisler@google.com Signed-off-by: Jonathan Corbet

tracing/histogram: Document variable stacktrace

2023-01-25T15:31:24+00:00

Add a little documentation (and a useful example) of how a stacktrace can be used within a histogram variable and synthetic event. Link: https://lkml.kernel.org/r/20230117152236.320181354@goodmis.org Cc: Masami Hiramatsu Cc: Andrew Morton Cc: Tom Zanussi Cc: Ross Zwisler Cc: Ching-lin Yu Signed-off-by: Steven Rostedt (Google)

tracing: docs: Update histogram doc for .percent/.graph and 'nohitcount'

2022-12-10T04:48:05+00:00

Update histogram document for .percent/.graph suffixes and 'nohitcount' option. Link: https://lore.kernel.org/linux-trace-kernel/166610815604.56030.4124933216911828519.stgit@devnote2 Signed-off-by: Masami Hiramatsu (Google) Reviewed-by: Tom Zanussi Tested-by: Tom Zanussi

tracing/histogram: Update document for KEYS_MAX size

2022-10-18T21:41:56+00:00

After commit 4f36c2d85ced ("tracing: Increase tracing map KEYS_MAX size"), 'keys' supports up to three fields. Signed-off-by: Zheng Yejian Cc: stable@vger.kernel.org Acked-by: Masami Hiramatsu (Google) Link: https://lore.kernel.org/r/20221017103806.2479139-1-zhengyejian1@huawei.com Signed-off-by: Jonathan Corbet

Delete duplicate words from kernel docs

2022-09-27T19:21:43+00:00

I have deleted duplicate words like to, guest, trace, when, we Signed-off-by: Akhil Raj Link: https://lore.kernel.org/r/20220829065239.4531-1-lf32.dev@gmail.com Signed-off-by: Jonathan Corbet

tracing/histogram: Update division by 0 documentation

2021-11-02T00:46:29+00:00

If the divisor is a constant and zero, the undeifned case can be detected and an error returned instead of -1. Link: https://lkml.kernel.org/r/20211029183339.3216491-3-kaleshsingh@google.com Cc: Jonathan Corbet Cc: Ingo Molnar Cc: Shuah Khan Cc: Tom Zanussi Signed-off-by: Kalesh Singh Signed-off-by: Steven Rostedt (VMware)