kernel/linux.git/tools/tracing/rtla/src/timerlat_hist.c, branch v7.2-rc1

rtla: Parse cmdline using libsubcmd

2026-05-28T11:02:48+00:00

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- 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

tools/rtla: Fix --dump-tasks usage in timerlat

2026-05-18T09:00:44+00:00

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 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

rtla: Introduce common_threshold_handler() helper

2026-03-10T09:32:37+00:00

Several functions duplicate the logic for handling threshold actions. When a threshold is reached, these functions stop the trace, perform configured actions, and restart the trace if --on-threshold continue is set. Create common_threshold_handler() to centralize this shared logic and avoid code duplication. The function executes the configured threshold actions and restarts the necessary trace instances when appropriate. Also add should_continue_tracing() helper to encapsulate the check for whether tracing should continue after a threshold event, improving code readability at call sites. In timerlat_top_bpf_main_loop(), use common_params directly instead of casting through timerlat_params when only common fields are needed. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260309195040.1019085-5-wander@redhat.com Signed-off-by: Tomas Glozar

rtla: Exit on memory allocation failures during initialization

2026-03-10T09:32:37+00:00

Most memory allocations in rtla happen during early initialization before any resources are acquired that would require cleanup. In these cases, propagating allocation errors just adds complexity without any benefit. There's nothing to clean up, and the program must exit anyway. This patch introduces fatal allocation wrappers (calloc_fatal, reallocarray_fatal, strdup_fatal) that call fatal() on allocation failure. These wrappers simplify the code by eliminating unnecessary error propagation paths. The patch converts early allocations to use these wrappers in actions_init() and related action functions, osnoise_context_alloc() and osnoise_init_tool(), trace_instance_init() and trace event functions, and parameter structure allocations in main functions. This simplifies the code while maintaining the same behavior: immediate exit on allocation failure during initialization. Allocations that require cleanup, such as those in histogram allocation functions with goto cleanup paths, are left unchanged and continue to return errors. Signed-off-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260309195040.1019085-2-wander@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Remove unneeded nr_cpus from for_each_monitored_cpu

2026-03-09T07:49:17+00:00

nr_cpus does not change at runtime, so passing it through the macro argument is unnecessary. Remove the argument and use the global nr_cpus instead. Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20260306194953.2511960-5-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Remove unneeded nr_cpus members

2026-03-09T07:49:17+00:00

nr_cpus does not change at runtime, so keeping it in struct members is unnecessary. Use the global nr_cpus instead of struct members. Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20260306194953.2511960-4-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Remove unneeded nr_cpus arguments

2026-03-09T07:49:17+00:00

nr_cpus does not change at runtime, so passing it through function arguments is unnecessary. Use the global nr_cpus instead of propagating it via parameters. Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20260306194953.2511960-3-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate nr_cpus usage across all tools

2026-03-09T07:49:16+00:00

sysconf(_SC_NPROCESSORS_CONF) (via get_nprocs_conf) reflects cpu_possible_mask, which is fixed at boot time, so querying it repeatedly is unnecessary. Replace multiple calls to sysconf(_SC_NPROCESSORS_CONF) with a single global nr_cpus variable initialized once at startup. `#pragma once` in timerlat_u.h is needed for pre-C23 compilers to avoid redefinition errors. Signed-off-by: Costa Shulyupin Link: https://lore.kernel.org/r/20260306194953.2511960-2-costa.shul@redhat.com Signed-off-by: Tomas Glozar

rtla/timerlat: Add --stack-format option

2026-03-04T14:51:56+00:00

In the current implementation, the auto-analysis code for printing the stack captured in the tracefs buffer of the aa instance stops at the first encountered address that cannot be resolved into a function symbol. This is not always the desired behavior on all platforms; sometimes, there might be resolvable entries after unresolvable ones, and sometimes, the user might want to inspect the raw pointers for the unresolvable entries. Add a new option, --stack-format, with three values: - truncate: stop at first unresolvable entry. This is the current behavior, and is kept as the default. - skip: skip unresolvable entries, but do not stop on them. - full: print all entries, including unresolvable ones. To make this work, the "size" field of the stack entry is now also read and used as the maximum number of entries to print, capped at 64, since that is the fixed length of the "caller" field. Link: https://lore.kernel.org/r/20260119115222.744150-1-tglozar@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Generate optstring from long options

2026-03-02T13:53:41+00:00

getopt_long() processes short and long options independently. RTLA, like the majority of applications, uses both short and long variants for each logical option. Since the val member of struct option holds the letter of the short variant, the string of short options can be reconstructed from the array of long options. Add getopt_auto() to generate optstring from an array of long options, eliminating the need to maintain separate short option strings. Signed-off-by: Costa Shulyupin Reviewed-by: Wander Lairson Costa Link: https://lore.kernel.org/r/20260108095011.2115719-1-costa.shul@redhat.com Signed-off-by: Tomas Glozar