tools/rtla: Improve exception handling in timerlat_load.py

The enhancements made to timerlat_load.py are intended to improve the script's exception handling.

Summary of the changes:
- Specific ex

tools/rtla: Improve exception handling in timerlat_load.py

The enhancements made to timerlat_load.py are intended to improve the script's exception handling.

Summary of the changes:
- Specific exceptions are now caught for CPU affinity and priority
settings, with clearer error messages provided.
- The timerlat file descriptor opening now includes handling for
PermissionError and OSError, with informative messages.
- In the infinite loop, generic exceptions have been replaced with
specific types like KeyboardInterrupt and IOError, improving feedback.

Before:
$ sudo python timerlat_load.py 122
Error setting affinity
After:
$ sudo python timerlat_load.py 122
Error setting affinity: [Errno 22] Invalid argument

Before:
$ sudo python timerlat_load.py 1 -p 950
Error setting priority
After:
$ sudo python timerlat_load.py 1 -p 950
Error setting priority: [Errno 22] Invalid argument

Before:
$ python timerlat_load.py 1
Error opening timerlat fd, did you run timerlat -U?
After:
$ python timerlat_load.py 1
Permission denied. Please check your access rights.

Cc: "[email protected]" <[email protected]>
Cc: "[email protected]" <[email protected]>
Link: https://lore.kernel.org/Q_k1s4hBtUy2px8ou0QKenjEK2_T_LoV8IxAE79aBakBogb-7uHp2fpET3oWtI1t3dy8uKjWeRzQOdKNzIzOOpyM4OjutJOriZ9TrGY6b-g=@protonmail.com
Signed-off-by: Furkan Onder <[email protected]>
Reviewed-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

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tools/rtla: Enhance argument parsing in timerlat_load.py

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

Summary of Changes:
- The cpu argument is

tools/rtla: Enhance argument parsing in timerlat_load.py

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: "[email protected]" <[email protected]>
Cc: "[email protected]" <[email protected]>
Link: https://lore.kernel.org/QfgO7ayKD9dsLk8_ZDebkAV0OF7wla7UmasbP9CBmui_sChOeizy512t3RqCHTjvQoUBUDP8dwEOVCdHQ5KvVNEiP69CynMY94SFDERWl94=@protonmail.com
Signed-off-by: Furkan Onder <[email protected]>
Reviewed-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

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tools/rtla: Improve code readability in timerlat_load.py

The enhancements made to timerlat_load.py are intended to improve the
script's robustness and readability.

Summary of the changes:
- Unneces

tools/rtla: Improve code readability in timerlat_load.py

The enhancements made to timerlat_load.py are intended to improve the
script's robustness and readability.

Summary of the changes:
- Unnecessary semicolons at the end of lines have been removed.
- Parentheses surrounding the if statement checking args.prio have been
eliminated.
- String concatenation for constructing timerlat_path has been replaced
with an f-string.
- Spacing in a multiplication expression has been adjusted for improved
clarity.

Cc: "[email protected]" <[email protected]>
Cc: "[email protected]" <[email protected]>
Link: https://lore.kernel.org/j2B-ted7pv3TaldTyqfIHrMmjq2fVyBFgnu3TskiQJsyRzy9loPTVVJoqHnrCWu5T88MDIFc612jUglH6Sxkdg9LN-I1XuITmoL70uECmus=@protonmail.com
Signed-off-by: Furkan Onder <[email protected]>
Reviewed-by: Tomas Glozar <[email protected]>
Signed-off-by: Steven Rostedt (Google) <[email protected]>

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tools/rtla: Add -U/--user-load option to timerlat

The timerlat tracer provides an interface for any application to wait
for the timerlat's periodic wakeup. Currently, rtla timerlat uses it
to dispat

tools/rtla: Add -U/--user-load option to timerlat

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 <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Signed-off-by: Daniel Bristot de Oliveira <[email protected]>

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