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path: root/Documentation/trace/user_events.rst
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2024-03-18tracing/user_events: Document multi-format flagBeau Belgrave
User programs can now ask user_events to handle the synchronization of multiple different formats for an event with the same name via the new USER_EVENT_REG_MULTI_FORMAT flag. Add a section for USER_EVENT_REG_MULTI_FORMAT that explains the intended purpose and caveats of using it. Explain how deletion works in these cases and how to use /sys/kernel/tracing/dynamic_events for per-version deletion. Link: https://lore.kernel.org/linux-trace-kernel/20240222001807.1463-5-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-10-03tracing/user_events: Document persist event flagsBeau Belgrave
Users need to know how to make events persist now that we allow for that. We also now allow the dynamic_events file to create events by utilizing the persist flag during event register. Add back in to documentation how /sys/kernel/tracing/dynamic_events can be used to create persistent user_events. Add a section under registering for the currently supported flags (USER_EVENT_REG_PERSIST) and the required permissions. Add a note under deleting that deleting a persistent event also requires sufficient permission. Link: https://lkml.kernel.org/r/20230912180704.1284-4-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-08-18Documentation: Fix typosBjorn Helgaas
Fix typos in Documentation. Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Link: https://lore.kernel.org/r/20230814212822.193684-4-helgaas@kernel.org Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2023-06-14tracing/user_events: Document auto-cleanup and remove dyn_event refsBeau Belgrave
Now user_events auto-cleanup upon the last reference by default. This makes it not possible to use the dynamics event file via tracefs. Document that auto-cleanup is enabled by default and remove the refernce to /sys/kernel/tracing/dynamic_events file to make this clear. Link: https://lkml.kernel.org/r/20230614163336.5797-7-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-03-29tracing/user_events: Update documentation for ABIBeau Belgrave
The ABI for user_events has changed from mmap() based to remote writes. Update the documentation to reflect these changes, add new section for unregistering events since lifetime is now tied to tasks instead of files. Link: https://lkml.kernel.org/r/20230328235219.203-10-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-01-31docs: ftrace: always use canonical ftrace pathRoss Zwisler
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 <zwisler@google.com> Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org> Link: https://lore.kernel.org/r/20230125213251.2013791-1-zwisler@google.com Signed-off-by: Jonathan Corbet <corbet@lwn.net>
2022-09-29tracing/user_events: Update ABI documentation to align to bits vs bytesBeau Belgrave
Update the documentation to reflect the new ABI requirements and how to use the byte index with the mask properly to check event status. Link: https://lkml.kernel.org/r/20220728233309.1896-7-beaub@linux.microsoft.com Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-04-02tracing/user_events: Remove eBPF interfacesBeau Belgrave
Remove eBPF interfaces within user_events to ensure they are fully reviewed. Link: https://lore.kernel.org/all/20220329165718.GA10381@kbox/ Link: https://lkml.kernel.org/r/20220329173051.10087-1-beaub@linux.microsoft.com Suggested-by: Alexei Starovoitov <alexei.starovoitov@gmail.com> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2022-02-10user_events: Add documentation fileBeau Belgrave
Add a documentation file about user_events with example code, etc. explaining how it may be used. Link: https://lkml.kernel.org/r/20220118204326.2169-13-beaub@linux.microsoft.com Acked-by: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Beau Belgrave <beaub@linux.microsoft.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>