Add a new option, -A/--aligned, that enables timerlat thread alignment
implemented on the kernel-side in commit 4245bf4dc58f ("tracing/osnoise:
Add option to align tlat threads"). The option takes an argument,
representing alignment between timerlat threads in microseconds.

The feature is modeled after the option of the same name in the
cyclictest tool.

Link: https://lore.kernel.org/r/20260527144928.2944472-1-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

In addition to testing all tool_parse_args() functions, test also all
callbacks used for parsing custom option formats.

The callbacks represent a middle layer between the parsing functions
and utility functions dedicated to checking specific argument formats,
for example, scheduling class and duration. Callback tests are run
before parsing functions to make sure any issue in the former is
reported before it is encountered through the latter.

Tests verify both successful parsing and proper rejection of invalid
inputs (via exit tests). To enable testing static callbacks, a pragma
once guard is added to timerlat.h for safe inclusion by cli_p.h.

Add dependency of UNIT_TESTS_IN on LIBSUBCMD_INCLUDES, as the new test
file tests/unit/cli_opt_callback.c includes cli_p.h which includes
subcmd/parse-options.h.

Link: https://lore.kernel.org/r/20260528103254.2990068-7-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Add a test suite for the _parse_args() function of each tool that checks
the params structures (struct common_params, struct osnoise_params,
struct timerlat_params) returned by them for correctness.

One test case is added per option, as well as a few special cases for
tricky combinations of options. Test cases are ordered the same as the
option arrays and help message to allow easy checking of whether all
options are covered.

This should help clarify what the proper command line behavior of RTLA
is in case there are holes in the documentation and verify that the
intended behavior is implemented correctly.

A few necessary changes to the unit tests were done as part of this
commit:

- Unit tests now also link to libsubcmd and its dependencies.
- A new global variable in_unit_test is added to RTLA's CLI interface,
  causing it to skip check for root if running in unit tests. This
  allows the CLI unit tests to run as non-root, like existing unit
  tests.

There is quite a lot of duplication, some of it is mitigated with macros,
but partially it is intentional so that future changes in behavior are
tracked across tools.

Link: https://lore.kernel.org/r/20260528103254.2990068-6-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

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>

In preparation for migrating RTLA to libsubcmd, build libsubcmd from the
appropriate directory next to the RTLA build proper, and link the
resulting object to RTLA.

libsubcmd uses str_error_r() and strlcpy() at several places. To support
these, also link the respective libraries from tools/lib.

For completeness, also add tools/include to include path. This will
allow other userspace functions and macros shipped with the kernel to be
used in RTLA; perf and bpftool, two other users of libsubcmd, already do
that.

To prevent a name conflict, rename RTLA's run_command() function to
run_tool_command(), and replace RTLA's own container_of implementation
with the one in tools/include/linux/container_of.h.

Assisted-by: Composer:composer-1
Link: https://lore.kernel.org/r/20260528103254.2990068-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Currently, actions_perform() only ever sets the continue flag (when
performing the continue action), but never resets it. That leads to
RTLA continuing tracing even if the continue action was not performed in
the current iteration.

For example, the following command:

$ rtla timerlat hist -T 100 --on-threshold shell,command='
    echo Spike!
    if [ -f /tmp/a ]
    then
      exit 1
    else
      touch /tmp/a
    fi' --on-threshold continue

should print Spike! at most once, because after hitting the threshold
for the first time, /tmp/a exists, the shell action will fail, and the
continue action is not performed. However, unless /tmp/a exists before
the measurement, it will print Spike! until stopped, as the continue
flag stays set.

Set the continue flag to false in the beginning of actions_perform() to
make RTLA continue only if the action was actually performed.

Fixes: 8d933d5c89e8 ("rtla/timerlat: Add continue action")
Link: https://lore.kernel.org/r/20260526102523.2662391-1-tglozar@redhat.com
[ correct Fixes tag to include 12 characters of hash ]
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Before, when rtla got a signal, it stopped the main trace but not the
record trace.  With "--on-end trace", this can lead to
save_trace_to_file() failing to keep up, especially on a debug kernel.
Plus, it adds post-stoppage noise to the trace file.

Signed-off-by: Crystal Wood <crwood@redhat.com>
Fixes: c73cab9dbed0 ("rtla/timerlat_hist: Stop timerlat tracer on signal")
Fixes: a4dfce7559d7 ("rtla/timerlat_top: Stop timerlat tracer on signal")
Fixes: 3aadb65db5d6 ("rtla/timerlat: Add action on end feature")
Link: https://lore.kernel.org/r/20260512173731.2151841-1-crwood@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Add unit tests covering all functions in the actions module, including
both valid and invalid inputs and all action types, except for
actions_perform(), where only shell and continue actions are tested.

To support testing multiple modules, the unit test build was modified so
that it links the entire rtla-in.o file. For this to work, the main()
function in rtla.c was declared weak, so that the unit test main is able
to override it.

Other included minor changes to unit tests are:

- Make unit test output verbose to show which tests are being run, now
  that we have more than 3 tests.
- Add unit_tests file to .gitignore.
- Split unit test sources to one file per test suite, and keep only
  main() function in unit_tests.c.
- Fix Makefile dependencies so that "make unit-tests" will rebuild the
  binary with the changes in the commit.

Also with the linking the entire rtla-in.o file, it now has rtla's
nr_cpus symbol, so the declaration in utils unit tests is made extern.

Assisted-by: Composer:composer-2-fast
Link: https://lore.kernel.org/r/20260424140244.958495-1-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Fix --dump-task to --dump-tasks in timerlat_hist usage string
and getopt_long table for consistency with timerlat_top.

Add missing --dump-tasks to timerlat_top usage synopsis.

Assisted-by: Claude:claude-opus-4-6
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Fixes: 2091336b9a8b ("rtla/timerlat_hist: Add auto-analysis support")
Link: https://lore.kernel.org/r/20260414185223.65353-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>

Pull RTLA updates from Steven Rostedt:

 - Simplify option parsing

   Auto-generate getopt_long() optstring for short options from long
   options array, avoiding the need to specify it manually and reducing
   the surface for mistakes.

 - Add unit tests

   Implement unit tests (make unit-tests) using libcheck, next to
   existing runtime tests (make check). Currently, three functions from
   utils.c are tested.

 - Add --stack-format option

   In addition to stopping stack pointer decoding (with -s/--stack
   option) on first unresolvable pointer, allow also skipping
   unresolvable pointers and displaying everything, configurable with a
   new option.

 - Unify number of CPUs into one global variable

   Use one global variable, nr_cpus, to store the number of CPUs instead
   of retrieving it and passing it at multiple places.

 - Fix behavior in various corner cases

   Make RTLA behave correctly in several corner cases: memory allocation
   failure, invalid value read from kernel side, thread creation
   failure, malformed time value input, and read/write failure or
   interruption by signal.

 - Improve string handling

   Simplify several places in the code that handle strings, including
   parsing of action arguments. A few new helper functions and variables
   are added for that purpose.

 - Get rid of magic numbers

   Few places handling paths use a magic number of 1024. Replace it with
   MAX_PATH and ARRAY_SIZE() macro.

 - Unify threshold handling

   Code that handles response to latency threshold is duplicated between
   tools, which has led to bugs in the past. Unify it into a new helper
   as much as possible.

 - Fix segfault on SIGINT during cleanup

   The SIGINT handler touches dynamically allocated memory. Detach it
   before freeing it during cleanup to prevent segmentation fault and
   discarding of output buffers. Also, properly document SIGINT handling
   while at it.

* tag 'trace-rtla-v7.1' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (28 commits)
  Documentation/rtla: Document SIGINT behavior
  rtla: Fix segfault on multiple SIGINTs
  rtla/utils: Fix loop condition in PID validation
  rtla/utils: Fix resource leak in set_comm_sched_attr()
  rtla/trace: Fix I/O handling in save_trace_to_file()
  rtla/trace: Fix write loop in trace_event_save_hist()
  rtla/timerlat: Simplify RTLA_NO_BPF environment variable check
  rtla: Use str_has_prefix() for option prefix check
  rtla: Enforce exact match for time unit suffixes
  rtla: Use str_has_prefix() for prefix checks
  rtla: Add str_has_prefix() helper function
  rtla: Handle pthread_create() failure properly
  rtla/timerlat: Add bounds check for softirq vector
  rtla: Simplify code by caching string lengths
  rtla: Replace magic number with MAX_PATH
  rtla: Introduce common_threshold_handler() helper
  rtla/actions: Simplify argument parsing
  rtla: Use strdup() to simplify code
  rtla: Exit on memory allocation failures during initialization
  tools/rtla: Remove unneeded nr_cpus from for_each_monitored_cpu
  ...