linux.git/tools/tracing/rtla/src/timerlat_top.c, branch v6.16

rtla: Set distinctive exit value for failed tests

2025-05-07T19:36:19+00:00

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 
Cc: John Kacur 
Cc: "Luis Claudio R. Goncalves" 
Cc: Eder Zulian 
Cc: Dan Carpenter 
Cc: Jan Stancek 
Link: https://lore.kernel.org/20250417185757.2194541-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin 
Reviewed-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

rtla: Unify apply_config between top and hist

2025-03-26T14:36:39+00:00

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 
Link: https://lore.kernel.org/20250320092500.101385-3-tglozar@redhat.com
Signed-off-by: Tomas Glozar 
Reviewed-by: John Kacur 
Signed-off-by: Steven Rostedt (Google)

rtla: Fix segfault in save_trace_to_file call

2025-03-26T14:35:20+00:00

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 
Cc: Luis Goncalves 
Cc: Costa Shulyupin 
Link: https://lore.kernel.org/20250313141034.299117-1-tglozar@redhat.com
Fixes: dc4d4e7c72d1 ("rtla: Refactor save_trace_to_file")
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

rtla: Refactor save_trace_to_file

2025-03-04T19:17:19+00:00

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 
Cc: John Kacur 
Cc: "Luis Claudio R. Goncalves" 
Cc: Eder Zulian 
Cc: Dan Carpenter 
Cc: Gabriele Monaco 
Link: https://lore.kernel.org/20250219115138.406075-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin 
Reviewed-by: Tomas Glozar 
Tested-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

rtla/timerlat_top: Use BPF to collect samples

2025-03-04T17:35:18+00:00

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 
Cc: Luis Goncalves 
Cc: Gabriele Monaco 
Cc: Clark Williams 
Link: https://lore.kernel.org/20250218145859.27762-8-tglozar@redhat.com
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

rtla/timerlat_top: Move divisor to update

2025-03-04T17:35:18+00:00

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 
Cc: Luis Goncalves 
Cc: Gabriele Monaco 
Cc: Clark Williams 
Link: https://lore.kernel.org/20250218145859.27762-7-tglozar@redhat.com
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

rtla/timerlat: Unify params struct

2025-03-04T17:35:17+00:00

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 
Cc: Luis Goncalves 
Cc: Gabriele Monaco 
Cc: Clark Williams 
Link: https://lore.kernel.org/20250218145859.27762-2-tglozar@redhat.com
Signed-off-by: Tomas Glozar 
Signed-off-by: Steven Rostedt (Google)

rtla: Report missed event count

2025-01-24T18:47:07+00:00

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 
Cc: Luis Goncalves 
Link: https://lore.kernel.org/20250123142339.990300-5-tglozar@redhat.com
Signed-off-by: Tomas Glozar 
Tested-by: Gabriele Monaco 
Signed-off-by: Steven Rostedt (Google)

tools/rtla: Add osnoise_trace_is_off()

2025-01-24T18:46:11+00:00

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 
Cc: "Luis Claudio R. Goncalves" 
Cc: Eder Zulian 
Cc: Dan Carpenter 
Cc: Tomas Glozar 
Cc: Gabriele Monaco 
Link: https://lore.kernel.org/20250115180055.2136815-1-costa.shul@redhat.com
Signed-off-by: Costa Shulyupin 
Signed-off-by: Steven Rostedt (Google)

rtla/timerlat_top: Set OSNOISE_WORKLOAD for kernel threads

2025-01-24T18:46:03+00:00

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 
Cc: Luis Goncalves 
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 
Signed-off-by: Steven Rostedt (Google)