[RFC 17/19] rtla: Add rtla timerlat documentation

[Daniel Bristot de Oliveira]

Man page for rtla timerlat tool.

Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Tom Zanussi <zanussi@xxxxxxxxxx>
Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx>
Cc: Juri Lelli <juri.lelli@xxxxxxxxxx>
Cc: Clark Williams <williams@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
Cc: linux-rt-users@xxxxxxxxxxxxxxx
Cc: linux-trace-devel@xxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
---
 .../rtla/Documentation/rtla-timerlat.txt      | 65 +++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100644 tools/tracing/rtla/Documentation/rtla-timerlat.txt

diff --git a/tools/tracing/rtla/Documentation/rtla-timerlat.txt b/tools/tracing/rtla/Documentation/rtla-timerlat.txt
new file mode 100644
index 000000000000..2b5ef9a9d6b0
--- /dev/null
+++ b/tools/tracing/rtla/Documentation/rtla-timerlat.txt
@@ -0,0 +1,65 @@
+rtla-timerlat(1)
+================
+
+NAME
+----
+rtla-timerlat - Measures the operating system timer latency
+
+SYNOPSIS
+--------
+*rtla timerlat* [MODE] ...
+
+DESCRIPTION
+-----------
+The rtla-timerlat(1) tool is an interface for the timerlat tracer. The
+timerlat tracer dispatches a kernel thread per-cpu. These threads set
+a periodic timer to wake themselves up and go back to sleep. After the
+wakeup, they collect and generate useful information for the debugging
+of operating system timer latency.
+
+The timerlat tracer outputs information in two ways. It periodically
+prints the timer latency at the timer 'IRQ' handler and the 'Thread' handler.
+It also provides information for each noise via the osnoise tracepoints.
+The rtla-timerlat-top(1) mode displays a summary of the periodic output
+from the timerlat tracer. The rtla-hist-hist(1) mode displays a histogram of
+each tracer event occurrence. For further details, please refer to the
+respective man page.
+
+MODES
+-----
+*top*::
+  Prints the summary from timerlat tracer.
+*hist*::
+  Prints a histogram of timerlat samples.
+
+If no MODE is given, the top mode is called, passing the arguments.
+
+OPTIONS
+-------
+*-h*, *--help*::
+  Display the help text.
+
+For other options, see the man page for the corresponding mode.
+
+SEE ALSO
+--------
+_rtla-timerlat-top(1)_, _rtla-timerlat-hist(1)_
+
+Timerlat tracer documentation: <https://www.kernel.org/doc/html/latest/trace/timerlat-tracer.html>
+
+AUTHOR
+------
+Written by Daniel Bristot de Oliveira <bristot@xxxxxxxxxx>
+
+REPORTING BUGS
+--------------
+Report bugs to <lkml@xxxxxxxxxxxxxxx>
+
+LICENSE
+-------
+rtla is Free Software licensed under the GNU GPLv2
+
+COPYING
+-------
+Copyright \(C) 2021 Red Hat, Inc. Free use of this software is granted under
+the terms of the GNU Public License (GPL).
-- 
2.31.1