kernel/linux.git/tools/tracing/rtla/src/timerlat.c, branch v6.19.11

tools/rtla: Fix unassigned nr_cpus

2025-11-20T12:15:54+00:00

In recently introduced timerlat_free(), the variable 'nr_cpus' is not assigned. Assign it with sysconf(_SC_NPROCESSORS_CONF) as done elsewhere. Remove the culprit: -Wno-maybe-uninitialized. The rest of the code is clean. Signed-off-by: Costa Shulyupin Reviewed-by: Tomas Glozar Fixes: 2f3172f9dd58 ("tools/rtla: Consolidate code between osnoise/timerlat and hist/top") Link: https://lore.kernel.org/r/20251002170846.437888-1-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Add for_each_monitored_cpu() helper

2025-11-20T12:15:53+00:00

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 Reviewed-by: Tomas Glozar Link: https://lore.kernel.org/r/20251002123553.389467-1-costa.shul@redhat.com Signed-off-by: Tomas Glozar

tools/rtla: Consolidate code between osnoise/timerlat and hist/top

2025-09-27T08:52:57+00:00

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 Cc: Costa Shulyupin Link: https://lore.kernel.org/20250907022325.243930-5-crwood@redhat.com Reviewed-by: Tomas Glozar Signed-off-by: Crystal Wood Signed-off-by: Steven Rostedt (Google)

tools/rtla: Create common_apply_config()

2025-09-27T08:52:46+00:00

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 Cc: Costa Shulyupin Link: https://lore.kernel.org/20250907022325.243930-4-crwood@redhat.com Reviewed-by: Tomas Glozar Signed-off-by: Crystal Wood Signed-off-by: Steven Rostedt (Google)

tools/rtla: Consolidate common parameters into shared structure

2025-09-27T08:51:18+00:00

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 Link: https://lore.kernel.org/20250907022325.243930-2-crwood@redhat.com Reviewed-by: Tomas Glozar Signed-off-by: Costa Shulyupin Signed-off-by: Crystal Wood Signed-off-by: Steven Rostedt (Google)

rtla/timerlat: Introduce enum timerlat_tracing_mode

2025-07-25T20:43:56+00:00

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 Cc: Luis Goncalves Cc: Arnaldo Carvalho de Melo Cc: Chang Yin Cc: Costa Shulyupin Cc: Crystal Wood Cc: Gabriele Monaco Link: https://lore.kernel.org/20250626123405.1496931-2-tglozar@redhat.com Signed-off-by: Tomas Glozar Signed-off-by: Steven Rostedt (Google)

rtla: Always set all tracer options

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

rtla currently only sets tracer options that are explicitly set by the user, with the exception of OSNOISE_WORKLOAD. This leads to improper behavior in case rtla is run with those options not set to the default value. rtla does reset them to the original value upon exiting, but that does not protect it from starting with non-default values set either by an improperly exited rtla or by another user of the tracers. For example, after running this command: $ echo 1 > /sys/kernel/tracing/osnoise/stop_tracing_us all runs of rtla will stop at the 1us threshold, even if not requested by the user: $ rtla osnoise hist Index CPU-000 CPU-001 1 8 5 2 5 9 3 1 2 4 6 1 5 2 1 6 0 1 8 1 1 12 0 1 14 1 0 15 1 0 over: 0 0 count: 25 21 min: 1 1 avg: 3.68 3.05 max: 15 12 rtla osnoise hit stop tracing Fix the problem by setting the default value for all tracer options if the user has not provided their own value. For most of the options, it's enough to just drop the if clause checking for the value being set. For cpus, "all" is used as the default value, and for osnoise default period and runtime, default values of the osnoise_data variable in trace_osnoise.c are used. Cc: Luis Goncalves Link: https://lore.kernel.org/20250320092500.101385-5-tglozar@redhat.com Fixes: 1eceb2fc2ca5 ("rtla/osnoise: Add osnoise top mode") Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode") Fixes: a828cd18bc4a ("rtla: Add timerlat tool and timelart top mode") Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Signed-off-by: Tomas Glozar Reviewed-by: John Kacur 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 exit status when returning from calls to usage()

2022-12-09T23:06:24+00:00

rtla_usage(), osnoise_usage() and timerlat_usage() all exit with an error status. However when these are called from help, they should exit with a non-error status. Fix this by passing the exit status to the functions. Note, although we remove the subsequent call to exit after calling usage, we leave it in at the end of a function to suppress the compiler warning "control reaches end of a non-void function". Link: https://lkml.kernel.org/r/20221107144313.22470-1-jkacur@redhat.com Signed-off-by: John Kacur Acked-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt (Google)

rtla/timerlat: Add timerlat hist mode

2022-01-13T22:02:43+00:00

The rtla hist hist mode displays a histogram of each tracer event occurrence, both for IRQ and timer latencies. The tool also allows many configurations of the timerlat tracer and the collection of the tracer output. Here is one example of the rtla timerlat hist mode output: ---------- %< ---------- [root@alien ~]# rtla timerlat hist -c 0-3 -d 1M # RTLA timerlat histogram # Time unit is microseconds (us) # Duration: 0 00:01:00 Index IRQ-000 Thr-000 IRQ-001 Thr-001 IRQ-002 Thr-002 IRQ-003 Thr-003 0 58572 0 59373 0 58691 0 58895 0 1 1422 57021 628 57241 1310 56160 1102 56805 2 6 2931 0 2695 0 3567 4 3031 3 1 40 0 53 0 260 0 142 4 0 7 0 5 0 6 0 17 5 0 2 0 5 0 7 0 4 6 0 0 0 2 0 1 0 1 8 0 0 0 0 0 0 0 1 over: 0 0 0 0 0 0 0 0 count: 60001 60001 60001 60001 60001 60001 60001 60001 min: 0 1 0 1 0 1 0 1 avg: 0 1 0 1 0 1 0 1 max: 3 5 1 6 1 6 2 8 ---------- >% ---------- Running - rtla timerlat hist --help provides information about the available options. Link: https://lkml.kernel.org/r/7049ed3c46b7d6aceab18ffe7770003dfc4ddceb.1639158831.git.bristot@kernel.org Cc: Tao Zhou Cc: Ingo Molnar Cc: Tom Zanussi Cc: Masami Hiramatsu Cc: Juri Lelli Cc: Clark Williams Cc: John Kacur Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Sebastian Andrzej Siewior Cc: Daniel Bristot de Oliveira Cc: linux-rt-users@vger.kernel.org Cc: linux-trace-devel@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Daniel Bristot de Oliveira Signed-off-by: Steven Rostedt