[ Upstream commit bd26818343dc02936a4f2f7b63368d5e1e1773c8 ]

The enhancements made to timerlat_load.py are aimed at improving the clarity of argument parsing.

Summary of Changes:
- The cpu argument is now specified as an integer type in the argument
  parser to enforce input validation, and the construction of affinity_mask
  has been simplified to directly use the integer value of args.cpu.
- The prio argument is similarly updated to be of integer type for
  consistency and validation, eliminating the need for the conversion of
  args.prio to an integer, as this is now handled by the argument parser.

Cc: "jkacur@redhat.com" <jkacur@redhat.com>
Cc: "lgoncalv@redhat.com" <lgoncalv@redhat.com>
Link: https://lore.kernel.org/QfgO7ayKD9dsLk8_ZDebkAV0OF7wla7UmasbP9CBmui_sChOeizy512t3RqCHTjvQoUBUDP8dwEOVCdHQ5KvVNEiP69CynMY94SFDERWl94=@protonmail.com
Signed-off-by: Furkan Onder <furkanonder@protonmail.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

The timerlat tracer provides an interface for any application to wait
for the timerlat's periodic wakeup. Currently, rtla timerlat uses it
to dispatch its user-space workload (-u option).

But as the tracer interface is generic, rtla timerlat can also be used
to monitor any workload that uses it. For example, a user might
place their own workload to wait on the tracer interface, and
monitor the results with rtla timerlat.

Add the -U option to rtla timerlat top and hist. With this option, rtla
timerlat will not dispatch its workload but only setting up the
system, waiting for a user to dispatch its workload.

The sample code in this patch is an example of python application
that loops in the timerlat tracer fd.

To use it, dispatch:

 # rtla timerlat -U

In a terminal, then run the python program on another terminal,
specifying the CPU to run it. For example, setting on CPU 1:

 #./timerlat_load.py 1

Then rtla timerlat will start printing the statistics of the
./timerlat_load.py app.

An interesting point is that the "Ret user Timer Latency" value
is the overall response time of the load. The sample load does
a memory copy to exemplify that.

The stop tracing options on rtla timerlat works in this setup
as well, including auto analysis.

Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org

Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>