Documentation/osnoise: Add osnoise/options documentation

Add the documentation about the osnoise/options file, along
with an explanation about the OSNOISE_WORKLOAD option.

Link: https://lkml.kernel.org/r/777af8f3d87beedd304805f98eff6c8291d64226.1668692096.git.bristot@kernel.org

Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
This commit is contained in:
Daniel Bristot de Oliveira 2022-11-17 14:46:20 +01:00 committed by Steven Rostedt (Google)
parent 30838fcd81
commit 67543cd6b8
1 changed files with 12 additions and 0 deletions

View File

@ -109,6 +109,11 @@ The tracer has a set of options inside the osnoise directory, they are:
- tracing_threshold: the minimum delta between two time() reads to be
considered as noise, in us. When set to 0, the default value will
be used, which is currently 5 us.
- osnoise/options: a set of on/off options that can be enabled by
writing the option name to the file or disabled by writing the option
name preceded with the 'NO_' prefix. For example, writing
NO_OSNOISE_WORKLOAD disables the OSNOISE_WORKLOAD option. The
special DEAFAULTS option resets all options to the default value.
Additional Tracing
------------------
@ -150,3 +155,10 @@ tracepoints is smaller than eight us reported in the sample_threshold.
The reason roots in the overhead of the entry and exit code that happens
before and after any interference execution. This justifies the dual
approach: measuring thread and tracing.
Running osnoise tracer without workload
---------------------------------------
By enabling the osnoise tracer with the NO_OSNOISE_WORKLOAD option set,
the osnoise: tracepoints serve to measure the execution time of
any type of Linux task, free from the interference of other tasks.