Documentation/rtla: Mention default cgroup state

The RTLA option -C/--cgroup is used to set a cgroup for workload
threads. This is either a specific cgroup, if passed an argument, or
rtla's cgroup, if no argument is given.

Expand the documentation of the -C option to also include the
information about the cgroup settings when the option is not specified.

Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20251010083338.478961-8-tglozar@redhat.com>

diff --git a/Documentation/tools/rtla/common_options.txt b/Documentation/tools/rtla/common_options.txt
index b842f065c8f68202c3eb9e64f9aa453fa1b29018..26e94d291a70c32c5ce4e50564741839b8587ed9 100644 (file)
--- a/Documentation/tools/rtla/common_options.txt
+++ b/Documentation/tools/rtla/common_options.txt
@@ -48,6 +48,8 @@
 
         Set a *cgroup* to the tracer's threads. If the **-C** option is passed without arguments, the tracer's thread will inherit **rtla**'s *cgroup*. Otherwise, the threads will be placed on the *cgroup* passed to the option.
 
+        If not set, the behavior differs between workload types. User workloads created by rtla will inherit rtla's cgroup. Kernel workloads are assigned the root cgroup.
+
 **--warm-up** *s*
 
         After starting the workload, let it run for *s* seconds before starting collecting the data, allowing the system to warm-up. Statistical data generated during warm-up is discarded.