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The "cpu" field of trace entries processed by rtla in tracefs mode is
used as an index into an array of size nr_cpus. In case the cpu numbers
mismatch because either the kernel or rtla reporting the number
incorrectly, out-of-bounds read/write may occur.
Guard against this by dropping trace entries with cpu >= nr_cpus in
collect_registered_events(). A new counter, "invalid_events", is added
to struct trace_instance, and printed (if non zero) next to the
pre-existing missed events counter.
Link: https://lore.kernel.org/r/20260814135511.2207190-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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A bug was reported when rtla-timerlat-top tool performs on-threshold
actions, even though no threshold was hit. This is reproduced even if no
threshold is set at all:
$ rtla timerlat top -q -c 0 --on-threshold shell,command='echo BAD'
BAD
Timer Latency
...
The bug is due to incorrect logic in timerlat_top_bpf_main_loop().
The loop uses timerlat_bpf_wait(), the return values of which are:
- > 0 (number of ringbuffer entries): at least 1 CPU hit threshold
- = 0: time out
- < 0: wait was interrupted by a signal
Commit 3138df6f0cd0 ("rtla/timerlat: Exit top main loop on any non-zero
wait_retval") changed the condition for "threshold hit" from
"wait_reval == 1" (exactly 1 CPU hit threshold) to "wait_retval != 0",
to fix a race where multiple CPUs hit the threshold at the same time.
That also made it incorrectly include a signal (< 0), coming from either
duration expired (SIGALRM) or user interrupt (SIGINT).
Check for wait_retval greater than zero in the if condition to cover all
return values correctly.
Fixes: 3138df6f0cd0 ("rtla/timerlat: Exit top main loop on any non-zero wait_retval")
Reported-by: Attila Fazekas <afazekas@redhat.com>
Reviewed-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260713141047.687877-1-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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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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>
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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 <wander@redhat.com>
Link: https://lore.kernel.org/r/20260309195040.1019085-5-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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 <wander@redhat.com>
Link: https://lore.kernel.org/r/20260309195040.1019085-2-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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 <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20260306194953.2511960-5-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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 <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20260306194953.2511960-4-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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 <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20260306194953.2511960-3-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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 <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20260306194953.2511960-2-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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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 <tglozar@redhat.com>
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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 <costa.shul@redhat.com>
Reviewed-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260108095011.2115719-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Remove unused includes for <errno.h> and <signal.h> to clean up the
code and reduce unnecessary dependencies.
Signed-off-by: Wander Lairson Costa <wander@redhat.com>
Link: https://lore.kernel.org/r/20260106133655.249887-12-wander@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of -H/--house-keeping.
Migrate the option parsing from individual tools to the
common_parse_options().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-8-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of -P/--priority.
Migrate the option parsing from individual tools to the
common_parse_options().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-7-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of -e/--event.
Migrate the option parsing from individual tools to the
common_parse_options().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-6-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of -d/--duration.
Migrate the option parsing from individual tools to the
common_parse_options().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-5-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of -D/--debug.
Migrate the option parsing from individual tools to the
common_parse_options().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-4-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of -C/--cgroup.
Migrate the option parsing from individual tools to the
common_parse_options().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-3-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of -c/--cpus.
Migrate the option parsing from individual tools to the
common_parse_options().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-2-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Each rtla tool duplicates parsing of many common options. This creates
maintenance overhead and risks inconsistencies when updating these
options.
Add common_parse_options() to centralize parsing of options used across
all tools.
Common options to be migrated in future patches.
Changes since v1:
- restore opterr
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251209100047.2692515-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Add option --bpf-action that allows the user to attach an external BPF
program that will be executed via BPF tail call on latency threshold
overflow.
Executing additional BPF code on latency threshold overflow allows doing
low-latency and in-kernel troubleshooting of the cause of the overflow.
The option takes an argument, which is a path to a BPF ELF file
expected to contain a function named "action_handler" in a section named
"tp/timerlat_action" (the section is necessary for libbpf to assign the
correct BPF program type to it).
Link: https://lore.kernel.org/r/20251126144205.331954-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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The rtla tools have significant code quadruplication in their usage
functions. Each tool implements its own version of the same help text
formatting and option descriptions, leading to maintenance overhead and
inconsistencies. Documentation/tools/rtla/common_options.rst lists 14
common options.
Add common_usage() infrastructure to consolidate help formatting.
Subsequent patches will extend this to handle other common options.
The refactored output is almost identical to the original, with the
following changes:
- add square brackets to specify optionality: `usage: [rtla] ...`
- remove `-q` from timerlat hist because hist tools don't support it
- minor spacing
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/r/20251124063204.845425-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Comparing to exactly 1 will fail if more than one ring buffer
event was seen since the last call to timerlat_bpf_wait(), which
can happen in some race scenarios.
Signed-off-by: Crystal Wood <crwood@redhat.com>
Link: https://lore.kernel.org/r/20251112152529.956778-5-crwood@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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When running rtla as
`rtla <timerlat|osnoise> <top|hist> -t custom_file.txt -a 100`
-a options override trace output filename specified by -t option.
Running the command above will create <timerlat|osnoise>_trace.txt file
instead of custom_file.txt. Fix this by making sure that -a option does
not override trace output filename even if it's passed after trace
output filename is specified.
Fixes: 173a3b014827 ("rtla/timerlat: Add the automatic trace option")
Signed-off-by: Ivan Pravdin <ipravdin.official@gmail.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/r/b6ae60424050b2c1c8709e18759adead6012b971.1762186418.git.ipravdin.official@gmail.com
[ use capital letter in subject, as required by tracing subsystem ]
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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Currently, user can only specify cgroup to the tracer's thread the
following ways:
`-C[cgroup]`
`-C[=cgroup]`
`--cgroup[=cgroup]`
If user tries to specify cgroup as `-C [cgroup]` or `--cgroup [cgroup]`,
the parser silently fails and rtla's cgroup is used for the tracer
threads.
To make interface more user-friendly, allow user to specify cgroup in
the aforementioned way, i.e. `-C [cgroup]` and `--cgroup [cgroup]`.
Refactor identical logic between -t/--trace and -C/--cgroup into a
common function.
Change documentation to reflect this user interface change.
Fixes: a957cbc02531 ("rtla: Add -C cgroup support")
Signed-off-by: Ivan Pravdin <ipravdin.official@gmail.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/r/16132f1565cf5142b5fbd179975be370b529ced7.1762186418.git.ipravdin.official@gmail.com
[ use capital letter in subject, as required by tracing subsystem ]
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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A long time ago, when the usage help was short, it was a favor
to the user to show it on error. Now that the usage help has
become very long, it is too noisy to dump the complete help text
for each typo after the error message itself.
Replace timerlat_top_usage("...\n") with fatal("...") on errors.
Remove the already unused 'usage' argument from timerlat_top_usage().
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/r/20251011082738.173670-3-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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The code contains some technical debt in error handling,
which complicates the consolidation of duplicated code.
Introduce an fatal() function to replace the common pattern of
err_msg() followed by exit(EXIT_FAILURE), reducing the length of an
already long function.
Further patches using fatal() follow.
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/r/20251011082738.173670-2-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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The longindex argument of getopt_long() is optional
and tied to the unused local variable option_index.
Remove it to shorten the four longest functions
and make the code neater.
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/r/20251002123553.389467-2-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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The rtla tools have many instances of iterating over CPUs while
checking if they are monitored.
Add a for_each_monitored_cpu() helper macro to make the code
more readable and reduce code duplication.
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Link: https://lore.kernel.org/r/20251002123553.389467-1-costa.shul@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
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The basic functionality came with the consolidation; now hook up the
command line options, and add documentation and tests.
Cc: John Kacur <jkacur@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/20250907022325.243930-8-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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Currently a lot of code is duplicated between the different rtla tools,
making maintenance more difficult, and encouraging divergence such as
features that are only implemented for certain tools even though they
could be more broadly applicable.
Merge the various main() functions into a common run_tool() with an ops
struct for tool-specific details.
Implement enough support for actions on osnoise to not need to keep the
old params->trace_output path.
Cc: John Kacur <jkacur@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/20250907022325.243930-5-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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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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The hist members were very similar between timerlat and top, so
just use one common hist struct.
output_divisor, quiet, and pretty printing are pretty generic
concepts that can go in the main struct even if not every
specific tool (currently) uses them.
Cc: John Kacur <jkacur@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/20250907022325.243930-3-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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timerlat_params and osnoise_params structures contain 15 identical
fields.
Introduce a new header common.h and define a common_params structure to
consolidate shared fields, reduce code duplication, and enhance
maintainability.
Cc: John Kacur <jkacur@redhat.com>
Link: https://lore.kernel.org/20250907022325.243930-2-crwood@redhat.com
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Signed-off-by: Crystal Wood <crwood@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Implement actions on end next to actions on threshold. A new option,
--on-end is added, parallel to --on-threshold. Instead of being
executed whenever a latency threshold is reached, it is executed at the
end of the measurement.
For example:
$ rtla timerlat hist -d 5s --on-end trace
will save the trace output at the end.
All actions supported by --on-threshold are also supported by --on-end,
except for continue, which does nothing with --on-end.
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/20250626123405.1496931-6-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Introduce option to resume tracing after a latency threshold overflow.
The option is implemented as an action named "continue".
Example:
$ rtla timerlat top -q -T 200 -d 1s --on-threshold \
exec,command="echo Threshold" --on-threshold continue
Threshold
Threshold
Threshold
Timer Latency
...
The feature is supported for both hist and top. After the continue
action is executed, processing of the list of actions is stopped and
tracing is resumed.
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/20250626123405.1496931-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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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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After the introduction of BPF-based sample collection, rtla-timerlat
effectively runs in one of three modes:
- Pure BPF mode, with tracefs only being used to set up the timerlat
tracer. Sample processing and stop on threshold are handled by BPF.
- tracefs mode. BPF is unsupported or kernel is lacking the necessary
trace event (osnoise:timerlat_sample). Stop on theshold is handled by
timerlat tracer stopping tracing in all instances.
- BPF/tracefs mixed mode - BPF is used for sample collection for top or
histogram, tracefs is used for trace output and/or auto-analysis. Stop
on threshold is handled both through BPF program, which stops sample
collection for top/histogram and wakes up rtla, and by timerlat
tracer, which stops tracing for trace output/auto-analysis instances.
Add enum timerlat_tracing_mode, with three values:
- TRACING_MODE_BPF
- TRACING_MODE_TRACEFS
- TRACING_MODE_MIXED
Those represent the modes described above. A field of this type is added
to struct timerlat_params, named "mode", replacing the no_bpf variable.
params->mode is set in timerlat_{top,hist}_parse_args to
TRACING_MODE_BPF or TRACING_MODE_MIXED based on whether trace output
and/or auto-analysis is requested. timerlat_{top,hist}_main then checks
if BPF is not unavailable or disabled, in that case, it sets
params->mode to TRACING_MODE_TRACEFS.
A condition is added to timerlat_apply_config that skips setting
timerlat tracer thresholds if params->mode is TRACING_MODE_BPF (those
are unnecessary, since they only turn off tracing, which is already
turned off in that case, since BPF is used to collect samples).
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/20250626123405.1496931-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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A test is considered failed when a sample trace exceeds the threshold.
Failed tests return the same exit code as passed tests, requiring test
frameworks to determine the result by searching for "hit stop tracing"
in the output.
Assign a distinct exit code for failed tests to enable the use of shell
expressions and seamless integration with testing frameworks without the
need to parse output.
Add enum type for return value.
Update `make check`.
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Eder Zulian <ezulian@redhat.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Jan Stancek <jstancek@redhat.com>
Link: https://lore.kernel.org/20250417185757.2194541-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The functions osnoise_top_apply_config and osnoise_hist_apply_config, as
well as timerlat_top_apply_config and timerlat_hist_apply_config, are
mostly the same.
Move common part from them into separate functions osnoise_apply_config
and timerlat_apply_config.
For rtla-timerlat, also unify params->user_hist and params->user_top
into one field called params->user_data, and move several fields used
only by timerlat-top into the top-only section of struct
timerlat_params.
Cc: Luis Goncalves <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20250320092500.101385-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Reviewed-by: John Kacur <jkacur@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Running rtla with exit on threshold, but without saving trace leads to a
segmenetation fault:
$ rtla timerlat hist -T 10
...
Max timerlat IRQ latency from idle: 4.29 us in cpu 0
Segmentation fault
This is caused by null pointer deference in the call of
save_trace_to_file, which attempts to dereference an uninitialized
osnoise_tool variable:
save_trace_to_file(record->trace.inst, params->trace_output);
^ this is uninitialized if params->trace_output is
not set
Fix this by not attempting to dereference "record" if it is NULL and
passing NULL instead. As a safety measure, the first field is also
checked for NULL inside save_trace_to_file.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Costa Shulyupin <costa.shul@redhat.com>
Link: https://lore.kernel.org/20250313141034.299117-1-tglozar@redhat.com
Fixes: dc4d4e7c72d1 ("rtla: Refactor save_trace_to_file")
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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The functions osnoise_hist_main(), osnoise_top_main(),
timerlat_hist_main(), and timerlat_top_main() are lengthy and contain
duplicated code.
Refactor by consolidating the duplicate lines into the
save_trace_to_file() function.
Cc: Daniel Bristot de Oliveira <bristot@kernel.org>
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Eder Zulian <ezulian@redhat.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250219115138.406075-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Reviewed-by: Tomas Glozar <tglozar@redhat.com>
Tested-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Collect samples using BPF program instead of pulling them from tracefs.
If the osnoise:timerlat_sample tracepoint is unavailable or the BPF
program fails to load for whatever reason, rtla falls back to the old
implementation.
The collection of samples using the BPF program is fully self-contained
and requires no activity of the userspace part of rtla during the
measurement. Thus, rtla only pulls the summary from the BPF map and
displays it every second, improving the performance.
In --aa-only mode, the BPF program does not collect any data and only
signalizes the end of tracing to userspace. An optimization that re-used
the main trace instance for auto-analysis in aa-only mode was dropped, as
rtla no longer turns tracing on in the main trace instance, making it
useless for auto-analysis.
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/20250218145859.27762-8-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Unlike timerlat-hist, timerlat-top applies the output divisor used to
set ns/us mode when printing results instead of applying it when
collecting the samples.
Move the application of the divisor from timerlat_top_print into
timerlat_top_update to make it consistent with timerlat-hist.
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/20250218145859.27762-7-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Instead of having separate structs timerlat_top_params and
timerlat_hist_params, use one struct timerlat_params for both.
This allows code using the structs to be shared between timerlat-top and
timerlat-hist.
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/20250218145859.27762-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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Print how many events were missed by trace buffer overflow in the main
instance at the end of the run (for hist) or during the run (for top).
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20250123142339.990300-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Tested-by: Gabriele Monaco <gmonaco@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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All of the users of trace_is_off() passes in &record->trace as the second
parameter, where record is a pointer to a struct osnoise_tool. This record
could be NULL and there is a hidden dependency that the trace field is the
first field to allow &record->trace to work with a NULL record pointer.
In order to make this code a bit more robust, as record shouldn't be
dereferenced if it is NULL, even if the code does work, create a new
function called osnoise_trace_is_off() that takes the pointer to a
struct osnoise_tool as its second parameter. This way it can properly test
if it is NULL before it dereferences it.
The old function trace_is_off() is removed and the function
osnoise_trace_is_off() is added into osnoise.c which is what the
struct osnoise_tool is associated with.
Cc: John Kacur <jkacur@redhat.com>
Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com>
Cc: Eder Zulian <ezulian@redhat.com>
Cc: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250115180055.2136815-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin <costa.shul@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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When using rtla timerlat with userspace threads (-u or -U), rtla
disables the OSNOISE_WORKLOAD option in
/sys/kernel/tracing/osnoise/options. This option is not re-enabled in a
subsequent run with kernel-space threads, leading to rtla collecting no
results if the previous run exited abnormally:
$ rtla timerlat top -u
^\Quit (core dumped)
$ rtla timerlat top -k -d 1s
Timer Latency
0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us)
CPU COUNT | cur min avg max | cur min avg max
The issue persists until OSNOISE_WORKLOAD is set manually by running:
$ echo OSNOISE_WORKLOAD > /sys/kernel/tracing/osnoise/options
Set OSNOISE_WORKLOAD when running rtla with kernel-space threads if
available to fix the issue.
Cc: stable@vger.kernel.org
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Link: https://lore.kernel.org/20250107144823.239782-4-tglozar@redhat.com
Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support")
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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If either SIGINT is received twice, or after a SIGALRM (that is, after
timerlat was supposed to stop), abort processing events currently left
in the tracefs buffer and exit immediately.
This allows the user to exit rtla without waiting for processing all
events, should that take longer than wanted, at the cost of not
processing all samples.
Cc: John Kacur <jkacur@redhat.com>
Cc: Luis Goncalves <lgoncalv@redhat.com>
Cc: Gabriele Monaco <gmonaco@redhat.com>
Link: https://lore.kernel.org/20250116144931.649593-6-tglozar@redhat.com
Signed-off-by: Tomas Glozar <tglozar@redhat.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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