--- name: "rtla-osnoise-top" section: "1" platform: "linux" package: "rtla" version: "6.12.107-1" release: "Debian 13 (Trixie)" platforms: ["linux"] url: "https://new.carta.tech/rtla-osnoise-top" --- # rtla-osnoise-top(1) Display a summary of the operating system noise ## NAME rtla-osnoise-top - Display a summary of the operating system noise ## SYNOPSIS **rtla osnoise top** \[*OPTIONS*\] ## DESCRIPTION The **rtla osnoise** tool is an interface for the *osnoise* tracer. The *osnoise* tracer dispatches a kernel thread per-cpu. These threads read the time in a loop while with preemption, softirq and IRQs enabled, thus allowing all the sources of operating system noise during its execution. The *osnoise*'s tracer threads take note of the delta between each time read, along with an interference counter of all sources of interference. At the end of each period, the *osnoise* tracer displays a summary of the results. **rtla osnoise top** collects the periodic summary from the *osnoise* tracer, including the counters of the occurrence of the interference source, displaying the results in a user-friendly format. The tool also allows many configurations of the *osnoise* tracer and the collection of the tracer output. ## OPTIONS - **-a**, **--auto** *us* Set the automatic trace mode. This mode sets some commonly used options while debugging the system. It is equivalent to use **-s** *us* **-T 1 -t**. - **-p**, **--period** *us* Set the *osnoise* tracer period in microseconds. - **-r**, **--runtime** *us* Set the *osnoise* tracer runtime in microseconds. - **-s**, **--stop** *us* Stop the trace if a single sample is higher than the argument in microseconds. If **-T** is set, it will also save the trace to the output. - **-S**, **--stop-total** *us* Stop the trace if the total sample is higher than the argument in microseconds. If **-T** is set, it will also save the trace to the output. - **-T**, **--threshold** *us* Specify the minimum delta between two time reads to be considered noise. The default threshold is *5 us*. - **-t**, **--trace** \[*file*\] Save the stopped trace to \[*file\|osnoise\_trace.txt*\]. - **-q**, **--quiet** Print only a summary at the end of the session. - **-c**, **--cpus** *cpu-list* Set the osnoise tracer to run the sample threads in the cpu-list. - **-H**, **--house-keeping** *cpu-list* Run rtla control threads only on the given cpu-list. - **-d**, **--duration** *time\[s\|m\|h\|d\]* Set the duration of the session. - **-D**, **--debug** Print debug info. - **-e**, **--event** *sys:event* Enable an event in the trace (**-t**) session. The argument can be a specific event, e.g., **-e** *sched:sched\_switch*, or all events of a system group, e.g., **-e** *sched*. Multiple **-e** are allowed. It is only active when **-t** or **-a** are set. - **--filter** *\* Filter the previous **-e** *sys:event* event with *\*. For further information about event filtering see \ . - **--trigger *\*** Enable a trace event trigger to the previous **-e** *sys:event*. If the *hist:* trigger is activated, the output histogram will be automatically saved to a file named *system\_event\_hist.txt*. For example, the command: rtla \ \ -t -e osnoise:irq\_noise --trigger="hist:key=desc,duration/1000:sort=desc,duration/1000:vals=hitcount" Will automatically save the content of the histogram associated to *osnoise:irq\_noise* event in *osnoise\_irq\_noise\_hist.txt*. For further information about event trigger see \ . - **-P**, **--priority** *o:prio\|r:prio\|f:prio\|d:runtime:period* Set scheduling parameters to the osnoise tracer threads, the format to set the priority are: - • *o:prio* - use SCHED\_OTHER with *prio*; - • *r:prio* - use SCHED\_RR with *prio*; - • *f:prio* - use SCHED\_FIFO with *prio*; - • *d:runtime\[us\|ms\|s\]:period\[us\|ms\|s\]* - use SCHED\_DEADLINE with *runtime* and *period* in nanoseconds. - **-C**, **--cgroup**\[*=cgroup*\] Set a *cgroup* to the tracer's threads. If the **-C** option is passed without arguments, the tracer's thread will inherit **rtla**'s *cgroup*. Otherwise, the threads will be placed on the *cgroup* passed to the option. - **--warm-up** *s* After starting the workload, let it run for *s* seconds before starting collecting the data, allowing the system to warm-up. Statistical data generated during warm-up is discarded. - **--trace-buffer-size *kB*** Set the per-cpu trace buffer size in kB for the tracing output. - **-h**, **--help** Print help menu. ## EXAMPLE In the example below, the **rtla osnoise top** tool is set to run with a real-time priority *FIFO:1*, on CPUs *0-3*, for *900ms* at each period (*1s* by default). The reason for reducing the runtime is to avoid starving the rtla tool. The tool is also set to run for *one minute* and to display a summary of the report at the end of the session: ``` [root@f34 ~]# rtla osnoise top -P F:1 -c 0-3 -r 900000 -d 1M -q Operating System Noise duration: 0 00:01:00 | time is in us CPU Period Runtime Noise % CPU Aval Max Noise Max Single HW NMI IRQ Softirq Thread 0 #59 53100000 304896 99.42580 6978 56 549 0 53111 1590 13 1 #59 53100000 338339 99.36282 8092 24 399 0 53130 1448 31 2 #59 53100000 290842 99.45227 6582 39 855 0 53110 1406 12 3 #59 53100000 204935 99.61405 6251 33 290 0 53156 1460 12 ``` ## SEE ALSO [**rtla-osnoise**(1)](/rtla-osnoise/1.md), [**rtla-osnoise-hist**(1)](/rtla-osnoise-hist/1.md) Osnoise tracer documentation: \< \ \> ## AUTHOR Written by Daniel Bristot de Oliveira \< \ \> ## REPORTING BUGS Report bugs to \< \ \> and \< \ \> ## LICENSE **rtla** is Free Software licensed under the GNU GPLv2 ## COPYING Copyright (C) 2021 Red Hat, Inc. Free use of this software is granted under the terms of the GNU Public License (GPL).