From 29380d4055e524de918c76a861df17d14a4b7224 Mon Sep 17 00:00:00 2001 From: Daniel Bristot de Oliveira Date: Fri, 10 Dec 2021 19:11:31 +0100 Subject: rtla: Add rtla timerlat documentation Man page for rtla timerlat tool. Link: https://lkml.kernel.org/r/78678b8d024bf5a3a79f831ac9441b96e8d2f56e.1639158831.git.bristot@kernel.org Cc: Tao Zhou Cc: Ingo Molnar Cc: Tom Zanussi Cc: Masami Hiramatsu Cc: Juri Lelli Cc: Clark Williams Cc: John Kacur Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Sebastian Andrzej Siewior Cc: Daniel Bristot de Oliveira Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt --- .../tools/rtla/common_timerlat_description.rst | 10 ++++ Documentation/tools/rtla/rtla-timerlat.rst | 57 ++++++++++++++++++++++ 2 files changed, 67 insertions(+) create mode 100644 Documentation/tools/rtla/common_timerlat_description.rst create mode 100644 Documentation/tools/rtla/rtla-timerlat.rst (limited to 'Documentation/tools') diff --git a/Documentation/tools/rtla/common_timerlat_description.rst b/Documentation/tools/rtla/common_timerlat_description.rst new file mode 100644 index 000000000000..321201cb8597 --- /dev/null +++ b/Documentation/tools/rtla/common_timerlat_description.rst @@ -0,0 +1,10 @@ +The **rtla timerlat** 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 enable the trace of the most relevant information via +**osnoise:** tracepoints. diff --git a/Documentation/tools/rtla/rtla-timerlat.rst b/Documentation/tools/rtla/rtla-timerlat.rst new file mode 100644 index 000000000000..44a49e6f302b --- /dev/null +++ b/Documentation/tools/rtla/rtla-timerlat.rst @@ -0,0 +1,57 @@ +================ +rtla-timerlat +================ +------------------------------------------- +Measures the operating system timer latency +------------------------------------------- + +:Manual section: 1 + +SYNOPSIS +======== +**rtla timerlat** [*MODE*] ... + +DESCRIPTION +=========== + +.. include:: common_timerlat_description.rst + +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** mode displays a summary of the periodic output +from the *timerlat* tracer. The **rtla hist hist** 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: + +AUTHOR +====== +Written by Daniel Bristot de Oliveira + +.. include:: common_appendix.rst -- cgit v1.2.3