linux-toradex.git/Documentation/tools/rtla, branch v6.16

Documentation/rtla: Include BPF sample collection

2025-04-14T16:42:55+00:00

Add dependencies needed to build rtla with BPF sample collection support
to README, and document both ways of sample collection in the manpages.

Signed-off-by: Tomas Glozar 
Acked-by: Steven Rostedt (Google) 
Reviewed-by: Luis Claudio R. Goncalves 
Signed-off-by: Jonathan Corbet 
Link: https://lore.kernel.org/r/20250311114936.148012-5-tglozar@redhat.com

Documentation/rtla: Fix typo in common_timerlat_description.rst

2025-04-14T16:42:55+00:00

Fix "it enable" to "it enables".

Fixes: 29380d4055e5 ("rtla: Add rtla timerlat documentation")
Signed-off-by: Tomas Glozar 
Reviewed-by: Luis Claudio R. Goncalves 
Signed-off-by: Jonathan Corbet 
Link: https://lore.kernel.org/r/20250311114936.148012-4-tglozar@redhat.com

Documentation/rtla: Fix typo in rtla-timerlat.rst

2025-04-14T16:42:55+00:00

The file says "rtla hist hist mode" instead of "rtla timerlat hist
mode".

Fix the typo.

Fixes: 29380d4055e5 ("rtla: Add rtla timerlat documentation")
Signed-off-by: Tomas Glozar 
Reviewed-by: Luis Claudio R. Goncalves 
Signed-off-by: Jonathan Corbet 
Link: https://lore.kernel.org/r/20250311114936.148012-3-tglozar@redhat.com

Documentation/rtla: Fix duplicate text about timerlat tracer

2025-04-14T16:42:55+00:00

A passage about how the timerlat tracer outputs information is included
in both common_timerlat_description.rst and rtla-timerlat.rst, leading
it to be displayed twice in the rtla-timerlat page.

Remove the duplicate passage from rtla-timerlat.rst.

Fixes: 29380d4055e5 ("rtla: Add rtla timerlat documentation")
Signed-off-by: Tomas Glozar 
Reviewed-by: Luis Claudio R. Goncalves 
Signed-off-by: Jonathan Corbet 
Link: https://lore.kernel.org/r/20250311114936.148012-2-tglozar@redhat.com

rtla: Documentation: Mention --deepest-idle-state

2024-10-17T21:13:16+00:00

Add --deepest-idle-state to manpage and mention libcpupower dependency
in README.txt.

Link: https://lore.kernel.org/20241017140914.3200454-7-tglozar@redhat.com
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

rtla: Documentation: Fix -t, --trace

2024-05-16T14:52:16+00:00

Move -t, --trace from common_options.rst to
common_osnoise_options.rst and
common_timerlat_options.rst

so that it will appear in the man pages

rtla-timerlat-hist.1
rtla-timerlat-top.1
rtla-osnoise-hist.1
rtla-osnoise-top.1

Remove the equals ('=') sign and add a space.

Link: https://lkml.kernel.org/r/20240516143121.12614-1-jkacur@redhat.com

Cc: Daniel Bristot de Oliveria 
Signed-off-by: John Kacur 
Signed-off-by: Daniel Bristot de Oliveira

rtla: Add --trace-buffer-size option

2024-05-16T14:44:34+00:00

Add the option allow the users to set a different buffer size for the
trace. For example, in large systems, the user might be interested on
reducing the trace buffer to avoid large tracing files.

The buffer size is specified in kB, and it is only affecting
the tracing instance.

The function trace_set_buffer_size() appears on libtracefs v1.6,
so increase the minimum required version on Makefile.config.

Link: https://lkml.kernel.org/r/e7c9ca5b3865f28e131a49ec3b984fadf2d056c6.1715860611.git.bristot@kernel.org

Cc: Jonathan Corbet 
Cc: Juri Lelli 
Cc: John Kacur 
Signed-off-by: Daniel Bristot de Oliveira

rtla/timerlat: Make user-space threads the default

2024-05-15T13:13:57+00:00

After ther -u addition, most of the known users are setting it. And
it makes sense, as it adds more information, and inherits the default
setup for the threads - e.g., cgroups configs.

Thus, if the user-space interface is available, enable -u. Otherwise,
use the in-kernel thread.

Add the -k option to allow the user to request kernel-threads.

Link: https://lkml.kernel.org/r/9241d3089de4091b124f780ed832a0e6646cadaa.1713968967.git.bristot@kernel.org

Cc: Jonathan Corbet 
Cc: Juri Lelli 
Signed-off-by: Daniel Bristot de Oliveira

rtla: Add the --warm-up option

2024-05-15T13:13:57+00:00

On many cases, the results right after the startup are different
from the rest of the execution, biasing the results. For example,
on osnoise, the scheduler might take some time to adapt to the new
busy-loop workload.

Add the --warm-up  option, adding a warm-up phase (in
seconds) where the workload is set, but the results are discarded.

Link: https://lkml.kernel.org/r/e682d5ce5af90f123bd13220f63d5c3d118a92be.1713968967.git.bristot@kernel.org

Cc: Jonathan Corbet 
Cc: Juri Lelli 
Signed-off-by: Daniel Bristot de Oliveira

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

2024-03-20T04:39:06+00:00

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 
Cc: Masami Hiramatsu 
Signed-off-by: Daniel Bristot de Oliveira