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2025-01-26Merge tag 'trace-tools-v6.14' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull rv and tools/rtla updates from Steven Rostedt: - Add a test suite to test the tool Add a small test suite that can be used to test rtla's basic features to at least have something to test when applying changes. - Automate manual steps in monitor creation While creating a new monitor in RV, besides generating code from dot2k, there are a few manual steps which can be tedious and error prone, like adding the tracepoints, makefile lines and kconfig, or selecting events that start the monitor in the initial state. Updates were made to try and automate as much as possible among those steps to make creating a new RV monitor much quicker. It is still requires to select proper tracepoints, this step is harder to automate in a general way and, in several cases, would still need user intervention. - Have rtla timerlat hist and top set OSNOISE_WORKLOAD flag Have both rtla-timerlat-hist and rtla-timerlat-top set OSNOISE_WORKLOAD to the proper value ("on" when running with -k, "off" when running with -u) every time the option is available instead of setting it only when running with -u. This prevents rtla timerlat -k from giving no results when NO_OSNOISE_WORKLOAD is set, either manually or by an abnormally exited earlier run of rtla timerlat -u. - Stop rtla timerlat on signal properly when overloaded There is an issue where if rtla is run on machines with a high number of CPUs (100+), timerlat can generate more samples than rtla is able to process via tracefs_iterate_raw_events. This is especially common when the interval is set to 100us (rteval and cyclictest default) as opposed to the rtla default of 1000us, but also happens with the rtla default. Currently, this leads to rtla hanging and having to be terminated with SIGTERM. SIGINT setting stop_tracing is not enough, since more and more events are coming and tracefs_iterate_raw_events never exits. To fix this: Stop the timerlat tracer on SIGINT/SIGALRM to ensure no more events are generated when rtla is supposed to exit. Also on receiving SIGINT/SIGALRM twice, abort iteration immediately with tracefs_iterate_stop, making rtla exit right away instead of waiting for all events to be processed. - Account for missed events Due to tracefs buffer overflow, it can happen that rtla misses events, making the tracing results inaccurate. Count both the number of missed events and the total number of processed events, and display missed events as well as their percentage. The numbers are displayed for both osnoise and timerlat, even though for the earlier, missed events are generally not expected. For hist, the number is displayed at the end of the run; for top, it is displayed on each printing of the top table. - Changes to make osnoise more robust There was a dependency in the code that the first field of the osnoise_tool structure was the trace field. If that that ever changed, then the code work break. Change the code to encapsulate this dependency where the code that uses the structure does not have this dependency. * tag 'trace-tools-v6.14' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: (22 commits) rtla: Report missed event count rtla: Add function to report missed events rtla: Count all processed events rtla: Count missed trace events tools/rtla: Add osnoise_trace_is_off() rtla/timerlat_top: Set OSNOISE_WORKLOAD for kernel threads rtla/timerlat_hist: Set OSNOISE_WORKLOAD for kernel threads rtla/osnoise: Distinguish missing workload option rtla/timerlat_top: Abort event processing on second signal rtla/timerlat_hist: Abort event processing on second signal rtla/timerlat_top: Stop timerlat tracer on signal rtla/timerlat_hist: Stop timerlat tracer on signal rtla: Add trace_instance_stop tools/rtla: Add basic test suite verification/dot2k: Implement event type detection verification/dot2k: Auto patch current kernel source verification/dot2k: Simplify manual steps in monitor creation rv: Simplify manual steps in monitor creation verification/dot2k: Add support for name and description options verification/dot2k: More robust template variables ...
2025-01-24rtla: Report missed event countTomas Glozar
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>
2025-01-24rtla: Add function to report missed eventsTomas Glozar
Add osnoise_report_missed_events to be used to report the number of missed events either during or after an osnoise or timerlat run. Also, display the percentage of missed events compared to the total number of received events. If an unknown number of missed events was reported during the run, the entire number of missed events is reported as unknown. Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/20250123142339.990300-4-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24rtla: Count all processed eventsTomas Glozar
Add a field processed_events to struct trace_instance and increment it in collect_registered_events, regardless of whether a handler is registered for the event. The purpose is to calculate the percentage of events that were missed due to tracefs buffer overflow. Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/20250123142339.990300-3-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24rtla: Count missed trace eventsTomas Glozar
Add function collect_missed_events to trace.c to act as a callback for tracefs_follow_missed_events, summing the number of total missed events into a new field missing_events of struct trace_instance. In case record->missed_events is negative, trace->missed_events is set to UINT64_MAX to signify an unknown number of events was missed. The callback is activated on initialization of the trace instance. Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/20250123142339.990300-2-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24tools/rtla: Add osnoise_trace_is_off()Costa Shulyupin
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>
2025-01-24rtla/timerlat_top: Set OSNOISE_WORKLOAD for kernel threadsTomas Glozar
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>
2025-01-24rtla/timerlat_hist: Set OSNOISE_WORKLOAD for kernel threadsTomas Glozar
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 hist -u ^\Quit (core dumped) $ rtla timerlat hist -k -d 1s Index over: count: min: avg: max: ALL: IRQ Thr Usr count: 0 0 0 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/20250107144823.239782-3-tglozar@redhat.com Fixes: ed774f7481fa ("rtla/timerlat_hist: Add timerlat user-space support") Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24rtla/osnoise: Distinguish missing workload optionTomas Glozar
osnoise_set_workload returns -1 for both missing OSNOISE_WORKLOAD option and failure in setting the option. Return -1 for missing and -2 for failure to distinguish them. Cc: stable@vger.kernel.org Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Link: https://lore.kernel.org/20250107144823.239782-2-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24rtla/timerlat_top: Abort event processing on second signalTomas Glozar
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>
2025-01-24rtla/timerlat_hist: Abort event processing on second signalTomas Glozar
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/20250116144931.649593-5-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24rtla/timerlat_top: Stop timerlat tracer on signalTomas Glozar
Currently, when either SIGINT from the user or SIGALRM from the duration timer is caught by rtla-timerlat, stop_tracing is set to break out of the main loop. This is not sufficient for cases where the timerlat tracer is producing more data than rtla can consume, since in that case, rtla is looping indefinitely inside tracefs_iterate_raw_events, never reaches the check of stop_tracing and hangs. In addition to setting stop_tracing, also stop the timerlat tracer on received signal (SIGINT or SIGALRM). This will stop new samples so that the existing samples may be processed and tracefs_iterate_raw_events eventually exits. Cc: stable@vger.kernel.org Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/20250116144931.649593-4-tglozar@redhat.com Fixes: a828cd18bc4a ("rtla: Add timerlat tool and timelart top mode") Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24rtla/timerlat_hist: Stop timerlat tracer on signalTomas Glozar
Currently, when either SIGINT from the user or SIGALRM from the duration timer is caught by rtla-timerlat, stop_tracing is set to break out of the main loop. This is not sufficient for cases where the timerlat tracer is producing more data than rtla can consume, since in that case, rtla is looping indefinitely inside tracefs_iterate_raw_events, never reaches the check of stop_tracing and hangs. In addition to setting stop_tracing, also stop the timerlat tracer on received signal (SIGINT or SIGALRM). This will stop new samples so that the existing samples may be processed and tracefs_iterate_raw_events eventually exits. Cc: stable@vger.kernel.org Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/20250116144931.649593-3-tglozar@redhat.com Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2025-01-24rtla: Add trace_instance_stopTomas Glozar
Support not only turning trace on for the timerlat tracer, but also turning it off. This will be used in subsequent patches to stop the timerlat tracer without also wiping the trace buffer. Cc: stable@vger.kernel.org Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Gabriele Monaco <gmonaco@redhat.com> Link: https://lore.kernel.org/20250116144931.649593-2-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-12-27rtla/timerlat: Fix histogram ALL for zero samplesTomas Glozar
rtla timerlat hist currently computers the minimum, maximum and average latency even in cases when there are zero samples. This leads to nonsensical values being calculated for maximum and minimum, and to divide by zero for average. A similar bug is fixed by 01b05fc0e5f3 ("rtla/timerlat: Fix histogram report when a cpu count is 0") but the bug still remains for printing the sum over all CPUs in timerlat_print_stats_all. The issue can be reproduced with this command: $ rtla timerlat hist -U -d 1s Index over: count: min: avg: max: Floating point exception (core dumped) (There are always no samples with -U unless the user workload is created.) Fix the bug by omitting max/min/avg when sample count is zero, displaying a dash instead, just like we already do for the individual CPUs. The logic is moved into a new function called format_summary_value, which is used for both the individual CPUs and for the overall summary. Cc: stable@vger.kernel.org Link: https://lore.kernel.org/20241127134130.51171-1-tglozar@redhat.com Fixes: 1462501c7a8 ("rtla/timerlat: Add a summary for hist mode") Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-11-22Merge tag 'trace-tools-v6.13' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace Pull tracing tools updates from Steven Rostedt: - Add ':' to getopt option 'trace-buffer-size' in timerlat_hist for consistency - Remove unused sched_getattr define - Rename sched_setattr() helper to syscall_sched_setattr() to avoid conflicts - Update counters to long from int to avoid overflow - Add libcpupower dependency detection - Add --deepest-idle-state to timerlat to limit deep idle sleeps - Other minor clean ups and documentation changes * tag 'trace-tools-v6.13' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace: verification/dot2: Improve dot parser robustness tools/rtla: Improve exception handling in timerlat_load.py tools/rtla: Enhance argument parsing in timerlat_load.py tools/rtla: Improve code readability in timerlat_load.py rtla/timerlat: Do not set params->user_workload with -U rtla: Documentation: Mention --deepest-idle-state rtla/timerlat: Add --deepest-idle-state for hist rtla/timerlat: Add --deepest-idle-state for top rtla/utils: Add idle state disabling via libcpupower rtla: Add optional dependency on libcpupower tools/build: Add libcpupower dependency detection rtla/timerlat: Make timerlat_hist_cpu->*_count unsigned long long rtla/timerlat: Make timerlat_top_cpu->*_count unsigned long long tools/rtla: fix collision with glibc sched_attr/sched_set_attr tools/rtla: drop __NR_sched_getattr rtla: Fix consistency in getopt_long for timerlat_hist rv: Fix a typo tools/rv: Correct the grammatical errors in the comments tools/rv: Correct the grammatical errors in the comments rtla: use the definition for stdout fd when calling isatty()
2024-11-19rtla/timerlat: Do not set params->user_workload with -UTomas Glozar
Since commit fb9e90a67ee9 ("rtla/timerlat: Make user-space threads the default"), rtla-timerlat has been defaulting to params->user_workload if neither that or params->kernel_workload is set. This has unintentionally made -U, which sets only params->user_hist/top but not params->user_workload, to behave like -u unless -k is set, preventing the user from running a custom workload. Example: $ rtla timerlat hist -U -c 0 & [1] 7413 $ python sample/timerlat_load.py 0 Error opening timerlat fd, did you run timerlat -U? $ ps | grep timerlatu 7415 pts/4 00:00:00 timerlatu/0 Fix the issue by checking for params->user_top/hist instead of params->user_workload when setting default thread mode. Link: https://lore.kernel.org/20241021123140.14652-1-tglozar@redhat.com Fixes: fb9e90a67ee9 ("rtla/timerlat: Make user-space threads the default") Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-17rtla/timerlat: Add --deepest-idle-state for histTomas Glozar
Support limiting deepest idle state also for timerlat-hist. Link: https://lore.kernel.org/20241017140914.3200454-6-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-17rtla/timerlat: Add --deepest-idle-state for topTomas Glozar
Add option to limit deepest idle state on CPUs where timerlat is running for the duration of the workload. Link: https://lore.kernel.org/20241017140914.3200454-5-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-17rtla/utils: Add idle state disabling via libcpupowerTomas Glozar
Add functions to utils.c to disable idle states through functions of libcpupower. This will serve as the basis for disabling idle states per cpu when running timerlat. Link: https://lore.kernel.org/20241017140914.3200454-4-tglozar@redhat.com Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-11rtla/timerlat: Make timerlat_hist_cpu->*_count unsigned long longTomas Glozar
Do the same fix as in previous commit also for timerlat-hist. Link: https://lore.kernel.org/20241011121015.2868751-2-tglozar@redhat.com Reported-by: Attila Fazekas <afazekas@redhat.com> Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-11rtla/timerlat: Make timerlat_top_cpu->*_count unsigned long longTomas Glozar
Most fields of struct timerlat_top_cpu are unsigned long long, but the fields {irq,thread,user}_count are int (32-bit signed). This leads to overflow when tracing on a large number of CPUs for a long enough time: $ rtla timerlat top -a20 -c 1-127 -d 12h ... 0 12:00:00 | IRQ Timer Latency (us) | Thread Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max 1 #43200096 | 0 0 1 2 | 3 2 6 12 ... 127 #43200096 | 0 0 1 2 | 3 2 5 11 ALL #119144 e4 | 0 5 4 | 2 28 16 The average latency should be 0-1 for IRQ and 5-6 for thread, but is reported as 5 and 28, about 4 to 5 times more, due to the count overflowing when summed over all CPUs: 43200096 * 127 = 5486412192, however, 1191444898 (= 5486412192 mod MAX_INT) is reported instead, as seen on the last line of the output, and the averages are thus ~4.6 times higher than they should be (5486412192 / 1191444898 = ~4.6). Fix the issue by changing {irq,thread,user}_count fields to unsigned long long, similarly to other fields in struct timerlat_top_cpu and to the count variable in timerlat_top_print_sum. Link: https://lore.kernel.org/20241011121015.2868751-1-tglozar@redhat.com Reported-by: Attila Fazekas <afazekas@redhat.com> Signed-off-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-10tools/rtla: fix collision with glibc sched_attr/sched_set_attrJan Stancek
glibc commit 21571ca0d703 ("Linux: Add the sched_setattr and sched_getattr functions") now also provides 'struct sched_attr' and sched_setattr() which collide with the ones from rtla. In file included from src/trace.c:11: src/utils.h:49:8: error: redefinition of ‘struct sched_attr’ 49 | struct sched_attr { | ^~~~~~~~~~ In file included from /usr/include/bits/sched.h:60, from /usr/include/sched.h:43, from /usr/include/tracefs/tracefs.h:10, from src/trace.c:4: /usr/include/linux/sched/types.h:98:8: note: originally defined here 98 | struct sched_attr { | ^~~~~~~~~~ Define 'struct sched_attr' conditionally, similar to what strace did: https://lore.kernel.org/all/20240930222913.3981407-1-raj.khem@gmail.com/ and rename rtla's version of sched_setattr() to avoid collision. Link: https://lore.kernel.org/8088f66a7a57c1b209cd8ae0ae7c336a7f8c930d.1728572865.git.jstancek@redhat.com Signed-off-by: Jan Stancek <jstancek@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-10tools/rtla: drop __NR_sched_getattrJan Stancek
It's not used since commit 084ce16df0f0 ("tools/rtla: Remove unused sched_getattr() function"). Link: https://lore.kernel.org/c355dc9ad23470098d6a8d0f31fbd702551c9ea8.1728552769.git.jstancek@redhat.com Signed-off-by: Jan Stancek <jstancek@redhat.com> Reviewed-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-04rtla: Fix consistency in getopt_long for timerlat_histGabriele Monaco
Commit e9a4062e1527 ("rtla: Add --trace-buffer-size option") adds a new long option to rtla utilities, but among all affected files, timerlat_hist misses a trailing `:` in the corresponding short option inside the getopt string (e.g. `\3:`). This patch propagates the `:`. Although this change is not functionally required, it improves consistency and slightly reduces the likelihood a future change would introduce a problem. Cc: John Kacur <jkacur@redhat.com> Cc: Luis Goncalves <lgoncalv@redhat.com> Cc: Tomas Glozar <tglozar@redhat.com> Link: https://lore.kernel.org/20240926143417.54039-1-gmonaco@redhat.com Signed-off-by: Gabriele Monaco <gmonaco@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-04rtla: use the definition for stdout fd when calling isatty()Eder Zulian
Use the STDOUT_FILENO definition when testing whether the standard output file descriptor refers to a terminal (for better redability). Link: https://lore.kernel.org/20240813142338.376039-1-ezulian@redhat.com Signed-off-by: Eder Zulian <ezulian@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-10-03rtla: Fix the help text in osnoise and timerlat top toolsEder Zulian
The help text in osnoise top and timerlat top had some minor errors and omissions. The -d option was missing the 's' (second) abbreviation and the error message for '-d' used '-D'. Cc: stable@vger.kernel.org Fixes: 1eceb2fc2ca54 ("rtla/osnoise: Add osnoise top mode") Fixes: a828cd18bc4ad ("rtla: Add timerlat tool and timelart top mode") Link: https://lore.kernel.org/20240813155831.384446-1-ezulian@redhat.com Suggested-by: Tomas Glozar <tglozar@redhat.com> Reviewed-by: Tomas Glozar <tglozar@redhat.com> Signed-off-by: Eder Zulian <ezulian@redhat.com> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-08-09rtla/osnoise: Prevent NULL dereference in error handlingDan Carpenter
If the "tool->data" allocation fails then there is no need to call osnoise_free_top() and, in fact, doing so will lead to a NULL dereference. Cc: stable@vger.kernel.org Cc: John Kacur <jkacur@redhat.com> Cc: "Luis Claudio R. Goncalves" <lgoncalv@redhat.com> Cc: Clark Williams <williams@redhat.com> Fixes: 1eceb2fc2ca5 ("rtla/osnoise: Add osnoise top mode") Link: https://lore.kernel.org/f964ed1f-64d2-4fde-ad3e-708331f8f358@stanley.mountain Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2024-06-21rtla/osnoise: Better report when histogram is emptyLuis Claudio R. Goncalves
When osnoise hist does not observe any samples above the threshold, no entries are recorded and the final report shows empty entries for the usual statistics (count, min, max, avg): [~]# osnoise hist -d 5s -T 500 # RTLA osnoise histogram # Time unit is microseconds (us) # Duration: 0 00:00:05 Index over: count: min: avg: max: That could lead users to confusing interpretations of the results. A simple solution is to report 0 for count and the statistics, making it clear that no noise (above the defined threshold) was observed: [~]# osnoise hist -d 5s -T 500 # RTLA osnoise histogram # Time unit is microseconds (us) # Duration: 0 00:00:05 Index over: 0 count: 0 min: 0 avg: 0 max: 0 Link: https://lkml.kernel.org/r/Zml6JmH5cbS7-HfZ@uudg.org Cc: Daniel Bristot de Oliveira <bristot@kernel.org> Cc: John Kacur <jkacur@redhat.com> Cc: Clark Williams <williams@redhat.com> Reviewed-by: John Kacur <jkacur@redhat.com> Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-06-21rtla/osnoise: Use pretty formatting only on interactive ttyLuis Claudio R. Goncalves
osnoise top performs background/font color formatting that could make the text output confusing if not on a terminal. Use the changes from commit f5c0cdad6684a ("rtla/timerlat: Use pretty formatting only on interactive tty") as an inspiration to fix this problem. Apply the formatting only if running on a tty, and not in quiet mode. Link: https://lkml.kernel.org/r/Zmb-yP_3EDHliI8Z@uudg.org Suggested-by: Daniel Bristot de Oliveira <bristot@kernel.org> Reviewed-by: John Kacur <jkacur@redhat.com> Reviewed-by: Clark Williams <williams@redhat.com> Signed-off-by: Luis Claudio R. Goncalves <lgoncalv@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-16rtla: Fix -t\--trace[=file]John Kacur
The -t option has an optional argument. The usual case is for a short option to be specified without an '=' and for the long version to be specified with an '=' Various forms of this do not work as expected. For example: rtla timerlat hist -T50 -tfile.txt will result in a truncated file name of "ile.txt" Another example is that the long form without the '=' will result in the default file name instead of the requested file name. This patch properly parses the optional argument with and without '=' and with and without spaces for the short form. This patch was also tested using -t and --trace without providing a file name both as the last requested option and with a following long and short option. For example: rtla timerlat hist -T50 -t -u rtla timerlat hist -T50 --trace -u This fix is applied to both timerlat top and hist and to osnoise top and hist. Here is the full testing for rtla timerlat hist. Before applying the patch rtla timerlat hist -T50 -t=file.txt Works as expected, "file.txt" rtla timerlat hist -T50 -tfile.txt Truncated file name "ile.txt" rtla timerlat hist -T50 -t file.txt Default file name instead of file.txt rtla timerlat hist -T50 --trace=file.txt Truncated file name "ile.txt" rtla timerlat hist -T50 --trace file.txt Default file name "timerlat_trace.txt" instead of "file.txt" After applying the patch: rtla timerlat hist -T50 -t=file.txt Works as expected, "file.txt" rtla timerlat hist -T50 -tfile.txt Works as expected, "file.txt" rtla timerlat hist -T50 -t file.txt Works as expected, "file.txt" rtla timerlat hist -T50 --trace=file.txt Works as expected, "file.txt" rtla timerlat hist -T50 --trace file.txt Works as expected, "file.txt" In addition the following tests were performed to make sure that the default file name worked as expected including with trailing options. rtla timerlat hist -T50 -t Works as expected "timerlat_trace.txt" rtla timerlat hist -T50 --trace Works as expected "timerlat_trace.txt" rtla timerlat hist -T50 -t -u Works as expected "timerlat_trace.txt" rtla timerlat hist -T50 --trace -u Works as expected "timerlat_trace.txt" Link: https://lkml.kernel.org/r/20240515183024.59985-1-jkacur@redhat.com Cc: Daniel Bristot de Oliveria <bristot@kernel.org> Signed-off-by: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-16rtla/timerlat: Fix histogram report when a cpu count is 0John Kacur
On short runs it is possible to get no samples on a cpu, like this: # rtla timerlat hist -u -T50 Index IRQ-001 Thr-001 Usr-001 IRQ-002 Thr-002 Usr-002 2 1 0 0 0 0 0 33 0 1 0 0 0 0 36 0 0 1 0 0 0 49 0 0 0 1 0 0 52 0 0 0 0 1 0 over: 0 0 0 0 0 0 count: 1 1 1 1 1 0 min: 2 33 36 49 52 18446744073709551615 avg: 2 33 36 49 52 - max: 2 33 36 49 52 0 rtla timerlat hit stop tracing IRQ handler delay: (exit from idle) 48.21 us (91.09 %) IRQ latency: 49.11 us Timerlat IRQ duration: 2.17 us (4.09 %) Blocking thread: 1.01 us (1.90 %) swapper/2:0 1.01 us ------------------------------------------------------------------------ Thread latency: 52.93 us (100%) Max timerlat IRQ latency from idle: 49.11 us in cpu 2 Note, the value 18446744073709551615 is the same as ~0. Fix this by reporting no results for the min, avg and max if the count is 0. Link: https://lkml.kernel.org/r/20240510190318.44295-1-jkacur@redhat.com Cc: stable@vger.kernel.org Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Suggested-by: Daniel Bristot de Oliveria <bristot@kernel.org> Signed-off-by: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-16rtla: Add --trace-buffer-size optionDaniel Bristot de Oliveira
Add the option allow the users to set a different buffer size for the trace. For example, in large systems, the user might be interested on reducing the trace buffer to avoid large tracing files. The buffer size is specified in kB, and it is only affecting the tracing instance. The function trace_set_buffer_size() appears on libtracefs v1.6, so increase the minimum required version on Makefile.config. Link: https://lkml.kernel.org/r/e7c9ca5b3865f28e131a49ec3b984fadf2d056c6.1715860611.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Cc: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Make user-space threads the defaultDaniel Bristot de Oliveira
After ther -u addition, most of the known users are setting it. And it makes sense, as it adds more information, and inherits the default setup for the threads - e.g., cgroups configs. Thus, if the user-space interface is available, enable -u. Otherwise, use the in-kernel thread. Add the -k option to allow the user to request kernel-threads. Link: https://lkml.kernel.org/r/9241d3089de4091b124f780ed832a0e6646cadaa.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla: Add the --warm-up optionDaniel Bristot de Oliveira
On many cases, the results right after the startup are different from the rest of the execution, biasing the results. For example, on osnoise, the scheduler might take some time to adapt to the new busy-loop workload. Add the --warm-up <seconds> option, adding a warm-up phase (in seconds) where the workload is set, but the results are discarded. Link: https://lkml.kernel.org/r/e682d5ce5af90f123bd13220f63d5c3d118a92be.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Add a summary for hist modeDaniel Bristot de Oliveira
Like on rtla timerlat top, add an overall summary at the bottom of timerlat hist. For instance: # timerlat hist -c 0-1 -d 10s -E 20 # RTLA timerlat histogram # Time unit is microseconds (us) # Duration: 0 00:00:10 Index IRQ-000 Thr-000 IRQ-001 Thr-001 6 1 0 0 0 7 1 0 0 0 8 1 0 1 0 9 7 0 0 0 10 16 0 0 0 11 1 0 3 0 15 0 0 3 0 16 0 0 12 0 17 0 0 28 0 18 0 2 26 0 19 1 1 80 1 over: 9973 9998 9848 10000 count: 10001 10001 10001 10001 min: 6 18 8 19 avg: 185 204 95 113 max: 428 450 341 371 ALL: IRQ Thr count: 20002 20002 min: 6 18 avg: 140 159 max: 428 450 Link: https://lkml.kernel.org/r/a6bc06c798f72127edc57d1f99da8d57e1187cee.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Suggested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Add a summary for top modeDaniel Bristot de Oliveira
While the per-cpu values are the results to take into consideration, the overall system values are also useful. Add a summary at the bottom of rtla timerlat top showing the overall results. For instance: Timer Latency 0 00:00:10 | IRQ Timer Latency (us) | Thread Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max 0 #10003 | 113 19 150 441 | 134 35 170 459 1 #10003 | 63 8 99 462 | 84 15 119 481 2 #10003 | 3 2 89 396 | 21 8 108 414 3 #10002 | 206 11 210 394 | 223 21 228 415 ---------------|----------------------------------------|--------------------------------------- ALL #40011 e0 | 2 137 462 | 8 156 481 Link: https://lkml.kernel.org/r/5eb510d6faeb4ce745e09395196752df75a2dd1a.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Suggested-by: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Use pretty formatting only on interactive ttyDaniel Bristot de Oliveira
timerlat top does some background/font color formatting. While useful on terminal, it breaks the output on other formats. For example, when piping the output for pastebin tools, the format strings are printed as characters. For instance: [2;37;40m Timer Latency [0;0;0m 0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us) [2;30;47mCPU COUNT | cur min avg max | cur min avg max[0;0;0m 0 #1013 | 1 0 1 54 | 5 2 4 57 1 #1013 | 3 0 1 10 | 6 2 4 15 To avoid this problem, do the formatting only if running on a tty, and in !quiet mode. Link: https://lkml.kernel.org/r/8288e1544ceab21557d5dda93a0f00339497c649.1713968967.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/auto-analysis: Replace \t with spacesDaniel Bristot de Oliveira
When copying timerlat auto-analysis from a terminal to some web pages or chats, the \t are being replaced with a single ' ' or ' ', breaking the output. For example: ## CPU 3 hit stop tracing, analyzing it ## IRQ handler delay: 1.30 us (0.11 %) IRQ latency: 1.90 us Timerlat IRQ duration: 3.00 us (0.24 %) Blocking thread: 1223.16 us (99.00 %) insync:4048 1223.16 us IRQ interference 4.93 us (0.40 %) local_timer:236 4.93 us ------------------------------------------------------------------------ Thread latency: 1235.47 us (100%) Replace \t with spaces to avoid this problem. Link: https://lkml.kernel.org/r/ec7ed2b2809c22ab0dfc8eb7c805ab9cddc4254a.1713968967.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Fixes: 27e348b221f6 ("rtla/timerlat: Add auto-analysis core") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-05-15rtla/timerlat: Simplify "no value" printing on topDaniel Bristot de Oliveira
Instead of printing three times the same output, print it only once, reducing lines and being sure that all no values have the same length. It also fixes an extra '\n' when running the with kernel threads, like here: =============== %< ============== Timer Latency 0 00:00:01 | IRQ Timer Latency (us) | Thread Timer Latency (us) CPU COUNT | cur min avg max | cur min avg max 2 #0 | - - - - | 161 161 161 161 3 #0 | - - - - | 161 161 161 161 8 #1 | 54 54 54 54 | - - - -'\n' ---------------|----------------------------------------|--------------------------------------- ALL #1 e0 | 54 54 54 | 161 161 161 =============== %< ============== This '\n' should have been removed with the user-space support that added another '\n' if not running with kernel threads. Link: https://lkml.kernel.org/r/0a4d8085e7cd706733a5dc10a81ca38b82bd4992.1713968967.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Juri Lelli <juri.lelli@redhat.com> Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-03-20tools/rtla: Add -U/--user-load option to timerlatDaniel Bristot de Oliveira
The timerlat tracer provides an interface for any application to wait for the timerlat's periodic wakeup. Currently, rtla timerlat uses it to dispatch its user-space workload (-u option). But as the tracer interface is generic, rtla timerlat can also be used to monitor any workload that uses it. For example, a user might place their own workload to wait on the tracer interface, and monitor the results with rtla timerlat. Add the -U option to rtla timerlat top and hist. With this option, rtla timerlat will not dispatch its workload but only setting up the system, waiting for a user to dispatch its workload. The sample code in this patch is an example of python application that loops in the timerlat tracer fd. To use it, dispatch: # rtla timerlat -U In a terminal, then run the python program on another terminal, specifying the CPU to run it. For example, setting on CPU 1: #./timerlat_load.py 1 Then rtla timerlat will start printing the statistics of the ./timerlat_load.py app. An interesting point is that the "Ret user Timer Latency" value is the overall response time of the load. The sample load does a memory copy to exemplify that. The stop tracing options on rtla timerlat works in this setup as well, including auto analysis. Link: https://lkml.kernel.org/r/36e6bcf18fe15c7601048fd4c65aeb193c502cc8.1707229706.git.bristot@kernel.org Cc: Jonathan Corbet <corbet@lwn.net> Cc: Masami Hiramatsu <mhiramat@kernel.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-03-20tools/rtla: Use tools/build makefiles to build rtlaDaniel Bristot de Oliveira
Use tools/build/ makefiles to build rtla, inheriting the benefits of it. For example, having a proper way to handle dependencies. rtla is built using perf infra-structure when building inside the kernel tree. At this point, rtla diverges from perf in two points: Documentation and tarball generation/build. At the documentation level, rtla is one step ahead, placing the documentation at Documentation/tools/rtla/, using the same build tools as kernel documentation. The idea is to move perf documentation to the same scheme and then share the same makefiles. rtla has a tarball target that the (old) RHEL8 uses. The tarball was kept using a simple standalone makefile for compatibility. The standalone makefile shares most of the code, e.g., flags, with regular buildings. The tarball method was set as deprecated. If necessary, we can make a rtla tarball like perf, which includes the entire tools/build. But this would also require changes in the user side (the directory structure changes, and probably the deps to build the package). Inspired on perf and objtool. Link: https://lkml.kernel.org/r/57563abf2715d22515c0c54a87cff3849eca5d52.1710519524.git.bristot@kernel.org Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Josh Poimboeuf <jpoimboe@kernel.org> Cc: John Kacur <jkacur@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Jiri Olsa <jolsa@kernel.org> Suggested-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Exit with EXIT_SUCCESS when help is invokedJohn Kacur
Fix rtla so that the following commands exit with 0 when help is invoked rtla osnoise top -h rtla osnoise hist -h rtla timerlat top -h rtla timerlat hist -h Link: https://lore.kernel.org/linux-trace-devel/20240203001607.69703-1-jkacur@redhat.com Cc: stable@vger.kernel.org Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Signed-off-by: John Kacur <jkacur@redhat.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Replace setting prio with nice for SCHED_OTHERlimingming3
Since the sched_priority for SCHED_OTHER is always 0, it makes no sence to set it. Setting nice for SCHED_OTHER seems more meaningful. Link: https://lkml.kernel.org/r/20240207065142.1753909-1-limingming3@lixiang.com Cc: stable@vger.kernel.org Fixes: b1696371d865 ("rtla: Helper functions for rtla") Signed-off-by: limingming3 <limingming3@lixiang.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Remove unused sched_getattr() functionDaniel Bristot de Oliveira
Clang is reporting: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c src/utils.c:241:19: warning: unused function 'sched_getattr' [-Wunused-function] 241 | static inline int sched_getattr(pid_t pid, struct sched_attr *attr, | ^~~~~~~~~~~~~ 1 warning generated. Which is correct, so remove the unused function. Link: https://lkml.kernel.org/r/eaed7ba122c4ae88ce71277c824ef41cbf789385.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: b1696371d865 ("rtla: Helper functions for rtla") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Fix clang warning about mount_point var sizeDaniel Bristot de Oliveira
clang is reporting this warning: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/utils.o src/utils.c src/utils.c:548:66: warning: 'fscanf' may overflow; destination buffer in argument 3 has size 1024, but the corresponding specifier may require size 1025 [-Wfortify-source] 548 | while (fscanf(fp, "%*s %" STR(MAX_PATH) "s %99s %*s %*d %*d\n", mount_point, type) == 2) { | ^ Increase mount_point variable size to MAX_PATH+1 to avoid the overflow. Link: https://lkml.kernel.org/r/1b46712e93a2f4153909514a36016959dcc4021c.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2024-02-12tools/rtla: Fix uninitialized bucket/data->bucket_size warningDaniel Bristot de Oliveira
When compiling rtla with clang, I am getting the following warnings: $ make HOSTCC=clang CC=clang LLVM_IAS=1 [..] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/osnoise_hist.o src/osnoise_hist.c src/osnoise_hist.c:138:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 138 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~ src/osnoise_hist.c:149:6: note: uninitialized use occurs here 149 | if (bucket < entries) | ^~~~~~ src/osnoise_hist.c:138:2: note: remove the 'if' if its condition is always true 138 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~~~~~~ 139 | bucket = duration / data->bucket_size; src/osnoise_hist.c:132:12: note: initialize the variable 'bucket' to silence this warning 132 | int bucket; | ^ | = 0 1 warning generated. [...] clang -O -g -DVERSION=\"6.8.0-rc3\" -flto=auto -fexceptions -fstack-protector-strong -fasynchronous-unwind-tables -fstack-clash-protection -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS $(pkg-config --cflags libtracefs) -c -o src/timerlat_hist.o src/timerlat_hist.c src/timerlat_hist.c:181:6: warning: variable 'bucket' is used uninitialized whenever 'if' condition is false [-Wsometimes-uninitialized] 181 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~ src/timerlat_hist.c:204:6: note: uninitialized use occurs here 204 | if (bucket < entries) | ^~~~~~ src/timerlat_hist.c:181:2: note: remove the 'if' if its condition is always true 181 | if (data->bucket_size) | ^~~~~~~~~~~~~~~~~~~~~~ 182 | bucket = latency / data->bucket_size; src/timerlat_hist.c:175:12: note: initialize the variable 'bucket' to silence this warning 175 | int bucket; | ^ | = 0 1 warning generated. This is a legit warning, but data->bucket_size is always > 0 (see timerlat_hist_parse_args()), so the if is not necessary. Remove the unneeded if (data->bucket_size) to avoid the warning. Link: https://lkml.kernel.org/r/6e1b1665cd99042ae705b3e0fc410858c4c42346.1707217097.git.bristot@kernel.org Cc: stable@vger.kernel.org Cc: Masami Hiramatsu <mhiramat@kernel.org> Cc: Nathan Chancellor <nathan@kernel.org> Cc: Nick Desaulniers <ndesaulniers@google.com> Cc: Bill Wendling <morbo@google.com> Cc: Justin Stitt <justinstitt@google.com> Cc: Donald Zickus <dzickus@redhat.com> Fixes: 1eeb6328e8b3 ("rtla/timerlat: Add timerlat hist mode") Fixes: 829a6c0b5698 ("rtla/osnoise: Add the hist mode") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-10-30rtla: Fix uninitialized variable foundColin Ian King
Variable found is not being initialized, in the case where the desired mount is not found the variable contains garbage. Fix this by initializing it to zero. Link: https://lore.kernel.org/all/20230727150117.627730-1-colin.i.king@gmail.com/ Fixes: a957cbc02531 ("rtla: Add -C cgroup support") Signed-off-by: Colin Ian King <colin.i.king@gmail.com> Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-09-22rtla/timerlat: Do not stop user-space if a cpu is offlineDaniel Bristot de Oliveira
If no CPU list is passed, timerlat in user-space will dispatch one thread per sysconf(_SC_NPROCESSORS_CONF). However, not all CPU might be available, for instance, if HT is disabled. Currently, rtla timerlat is stopping the session if an user-space thread cannot set affinity to a CPU, or if a running user-space thread is killed. However, this is too restrictive. So, reduce the error to a debug message, and rtla timerlat run as long as there is at least one user-space thread alive. Link: https://lore.kernel.org/lkml/59cf2c882900ab7de91c6ee33b382ac7fa6b4ed0.1694781909.git.bristot@kernel.org Fixes: cdca4f4e5e8e ("rtla/timerlat_top: Add timerlat user-space support") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
2023-09-12rtla/timerlat_aa: Fix previous IRQ delay for IRQs that happens after thread ↵Daniel Bristot de Oliveira
sample timerlat auto-analysis takes note of all IRQs, before or after the execution of the timerlat thread. Because we cannot go backward in the trace (we will fix it when moving to trace-cmd lib?), timerlat aa take note of the last IRQ execution in the waiting for the IRQ state, and then print it if it is executed after the expected timer IRQ starting time. After the thread sample, the timerlat starts recording the next IRQs as "previous" irq for the next occurrence. However, if an IRQ happens after the thread measurement but before the tracing stops, it is classified as a previous IRQ. That is not wrong, as it can be "previous" for the subsequent activation. What is wrong is considering it as a potential source for the last activation. Ignore the IRQ interference that happens after the IRQ starting time for now. A future improvement for timerlat can be either keeping a list of previous IRQ execution or using the trace-cmd library. Still, it requires further investigation - it is a new feature. Link: https://lore.kernel.org/lkml/a44a3f5c801dcc697bacf7325b65d4a5b0460537.1691162043.git.bristot@kernel.org Fixes: 27e348b221f6 ("rtla/timerlat: Add auto-analysis core") Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
generated by cgit (git 2.34.1) at 2025-07-15 20:56:24 +0000