rtla: Parse cmdline using libsubcmd

Instead of using getopt_long() directly to parse the command line
arguments given to an RTLA tool, use libsubcmd's parse_options().

Utilizing libsubcmd for parsi

rtla: Parse cmdline using libsubcmd

Instead of using getopt_long() directly to parse the command line
arguments given to an RTLA tool, use libsubcmd's parse_options().

Utilizing libsubcmd for parsing command line arguments has several
benefits:

- A help message is automatically generated by libsubcmd from the
specification, removing the need of writing it by hand.
- Options are sorted into groups based on which part of tracing (CPU,
thread, auto-analysis, tuning, histogram) they relate to.
- Common parsing patterns for numerical and boolean values now share
code, with the target variable being stored in the option array.

To avoid duplication of the option parsing logic, RTLA-specific
macros defining struct option values are created:

- RTLA_OPT_* for options common to all tools
- OSNOISE_OPT_* and TIMERLAT_OPT_* for options specific to
osnoise/timerlat tools
- HIST_OPT_* macros for options specific to histogram-based tools.

Individual *_parse_args() functions then construct an array out of
these macros that is then passed to libsubcmd's parse_options().

All code specific to command line options parsing is moved out of the
individual tool files into a new file, cli.c, which also contains the
contents of the rtla.c file. A private header, cli_p.h, is added
alongside the public header cli.h, so that unit tests are able to test
statically declared option callbacks.

Minor changes:

- The return value of tool-level help option changes to 129, as this is
the value set by libsubcmd; this is reflected in affected test cases.
The implementation of help for command-level and tracer-level help
is set to 129 as well for consistency, and the change is reflected in
exit value documentation.
- Related to the above, {rtla,osnoise,timerlat}_usage() are marked
__noreturn and exit() is removed from after they are called for
cleaner code.
- The error messages for invalid argument for options --dma-latency and
-E/--entries were corrected, fixing off-by-one in the limits.

Note that unsetting options (using --no-<opt> syntax) is currently not
implemented for options that use custom callbacks. For --irq and
--thread, it will never be implemented, as they conflict with already
existing --no-irq and --no-thread with a different meaning.

Assisted-by: Composer:composer-1.5
Link: https://lore.kernel.org/r/20260528103254.2990068-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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tools/rtla: Create common_apply_config()

Merge the common bits of osnoise_apply_config() and
timerlat_apply_config(). Put the result in a new common.c, and move
enough things to common.h so that co

tools/rtla: Create common_apply_config()

Merge the common bits of osnoise_apply_config() and
timerlat_apply_config(). Put the result in a new common.c, and move
enough things to common.h so that common.c does not need to include
osnoise.h.

Cc: John Kacur <jkacur@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/20250907022325.243930-4-crwood@redhat.com
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Crystal Wood <crwood@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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rtla/timerlat: Add action on threshold feature

Extend the functionality provided by the -t/--trace option, which
triggers saving the contents of a tracefs buffer after tracing is
stopped, to support

rtla/timerlat: Add action on threshold feature

Extend the functionality provided by the -t/--trace option, which
triggers saving the contents of a tracefs buffer after tracing is
stopped, to support implementing arbitrary actions.

A new option, --on-threshold, is added, taking an argument
that further specifies the action. Actions added in this patch are:

- trace[,file=<filename>]: Saves tracefs buffer, optionally taking a
filename.
- signal,num=<sig>,pid=<pid>: Sends signal to process. "parent" might
be specified instead of number to send signal to parent process.
- shell,command=<command>: Execute shell command.

Multiple actions may be specified and will be executed in order,
including multiple actions of the same type. Trace output requested via
-t and -a now adds a trace action to the end of the list.

If an action fails, the following actions are not executed. For
example, this command:

$ rtla timerlat -T 20 --on-threshold trace \
--on-threshold shell,command="grep ipi_send timerlat_trace.txt" \
--on-threshold signal,num=2,pid=parent

will send signal 2 (SIGINT) to parent process, but only if saved trace
contains the text "ipi_send".

This way, the feature can be used for flexible reactions on latency
spikes, and allows combining rtla with other tooling like perf.

Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Chang Yin <cyin@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Cc: Crystal Wood <crwood@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250626123405.1496931-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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rtla/timerlat: Add BPF skeleton to collect samples

Add BPF program that attaches to the osnoise:timerlat_sample tracepoint
and collects both the summary and the histogram (if requested) into BPF
map

rtla/timerlat: Add BPF skeleton to collect samples

Add BPF program that attaches to the osnoise:timerlat_sample tracepoint
and collects both the summary and the histogram (if requested) into BPF
maps (one map of each kind per context).

The program is designed to be used for both timerlat-top and
timerlat-hist. If using with timerlat-top, the "entries" parameter is
set to zero, which prevents the BPF program from recording histogram
entries. In that case, the maps for histograms do not have to be
created, as the BPF verifier will identify the code using them as
unreachable.

An IRQ or thread latency threshold might be supplied to stop recording
if hit, similar to the timerlat tracer threshold, which stops ftrace
tracing if hit. A BPF ringbuffer is used to signal threshold overflow to
userspace. In aa-only mode, this is the only function of the BPF
program.

Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Cc: Clark Williams <williams@redhat.com>
Link: https://lore.kernel.org/20250218145859.27762-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>

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tools/rtla: Use tools/build makefiles to build rtla

Use tools/build/ makefiles to build rtla, inheriting the benefits of
it. For example, having a proper way to handle dependencies.

rtla is built u

tools/rtla: Use tools/build makefiles to build rtla

Use tools/build/ makefiles to build rtla, inheriting the benefits of
it. For example, having a proper way to handle dependencies.

rtla is built using perf infra-structure when building inside the
kernel tree.

At this point, rtla diverges from perf in two points: Documentation
and tarball generation/build.

At the documentation level, rtla is one step ahead, placing the
documentation at Documentation/tools/rtla/, using the same build
tools as kernel documentation. The idea is to move perf
documentation to the same scheme and then share the same makefiles.

rtla has a tarball target that the (old) RHEL8 uses. The tarball was
kept using a simple standalone makefile for compatibility. The
standalone makefile shares most of the code, e.g., flags, with
regular buildings.

The tarball method was set as deprecated. If necessary, we can make
a rtla tarball like perf, which includes the entire tools/build.
But this would also require changes in the user side (the directory
structure changes, and probably the deps to build the package).

Inspired on perf and objtool.

Link: https://lkml.kernel.org/r/57563abf2715d22515c0c54a87cff3849eca5d52.1710519524.git.bristot@kernel.org

Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Josh Poimboeuf <jpoimboe@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>

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