tools/rv: Add support for nested monitors

RV now supports nested monitors, this functionality requires a container
monitor, which has virtually no functionality besides holding other
monitors, and nested monitors, that have a container as parent.

Nested monitors' sysfs folders are physically nested in the container's
folder, and they are listed in the available_monitors file with the
notation container:monitor.
These changes go against the assumption that each line in the
available_monitors file correspond to a folder in the rv directory,
breaking the functionality of the rv tool.

Add support for nested containers in the rv userspace tool, indenting
nested monitors while listed and allowing both the notation with and
without container name, which are equivalent:

  # rv list
  mon1
  mon2
  container:
   - nested1
   - nested2

  ## notation with container name
  # rv mon container:nested1

  ## notation without container name
  # rv mon nested1

Either way, enabling a nested monitor is the same as enabling any other
non-nested monitor.
Selecting the container with rv mon enables all the nested monitors, if
-t is passed, the trace also includes the monitor name next to the
event:

  # rv mon nested1 -t
  <idle>-0        [004] event   state1 x event    -> state2
  <idle>-0        [004] error   event not expected in state2

  # rv mon sched -t
  <idle>-0        [004] event_nested1   state1 x event    -> state2
  <idle>-0        [004] error_nested1   event not expected in state2

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Link: https://lore.kernel.org/20250305140406.350227-7-gmonaco@redhat.com
Signed-off-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

0 files changed, 0 insertions, 0 deletions