Commit 2784d74b authored by Linus Torvalds's avatar Linus Torvalds
Browse files

Merge tag 'trace-tools-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace 

Pull tracing tooling updates from Steven Rostedt:

 - Add cgroup support for rtla via the -C option

 - Add --house-keeping option that tells rtla where to place the
   housekeeping threads

 - Have rtla/timerlat have its own tracing instance instead of using the
   top level tracing instance that is the default for other tracing
   users to use

 - Add auto analysis to timerlat_hist

 - Have rtla start the tracers after creating the instances

 - Reduce rtla hwnoise down to 75% from 100% as it runs with preemption
   disabled and can cause system instability at 100%

 - Add support to run timerlat_top and timerlat_hist threads in
   user-space instead of just using the kernel tasks

 - Some minor clean ups and documentation changes

* tag 'trace-tools-v6.5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
  Documentation: Add tools/rtla timerlat -u option documentation
  rtla/timerlat_hist: Add timerlat user-space support
  rtla/timerlat_top: Add timerlat user-space support
  rtla/hwnoise: Reduce runtime to 75%
  rtla: Start the tracers after creating all instances
  rtla/timerlat_hist: Add auto-analysis support
  rtla/timerlat: Give timerlat auto analysis its own instance
  rtla: Automatically move rtla to a house-keeping cpu
  rtla: Change monitored_cpus from char * to cpu_set_t
  rtla: Add --house-keeping option
  rtla: Add -C cgroup support
parents 2a95b03d 61273832

Documentation/tools/rtla/common_options.rst

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        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.
@@ -42,6 +46,10 @@ 
        - *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.



**-h**, **--help**



        Print help menu.

Documentation/tools/rtla/common_timerlat_aa.rst

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**--no-aa**



        disable auto-analysis, reducing rtla timerlat cpu usage
 


**--aa-only** *us*



        Set stop tracing conditions and run without collecting and displaying statistics.

        Print the auto-analysis if the system hits the stop tracing condition. This option

        is useful to reduce rtla timerlat CPU, enabling the debug without the overhead of

        collecting the statistics.

Documentation/tools/rtla/common_timerlat_options.rst

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        Set the /dev/cpu_dma_latency to *us*, aiming to bound exit from idle latencies.

        *cyclictest* sets this value to *0* by default, use **--dma-latency** *0* to have

        similar results.



**-u**, **--user-threads**



        Set timerlat to run without a workload, and then dispatches user-space workloads

        to wait on the timerlat_fd. Once the workload is awakes, it goes to sleep again

        adding so the measurement for the kernel-to-user and user-to-kernel to the tracer

        output.

Documentation/tools/rtla/rtla-timerlat-hist.rst

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.. include:: common_options.rst



.. include:: common_timerlat_aa.rst



EXAMPLE

=======

In the example below, **rtla timerlat hist** is set to run for *10* minutes,

in the cpus *0-4*, *skipping zero* only lines. Moreover, **rtla timerlat

hist** will change the priority of the *timerlat* threads to run under

*SCHED_DEADLINE* priority, with a *10us* runtime every *1ms* period. The

*1ms* period is also passed to the *timerlat* tracer::

*1ms* period is also passed to the *timerlat* tracer. Auto-analysis is disabled

to reduce overhead ::



  [root@alien ~]# timerlat hist -d 10m -c 0-4 -P d:100us:1ms -p 1ms

  [root@alien ~]# timerlat hist -d 10m -c 0-4 -P d:100us:1ms -p 1ms --no-aa

  # RTLA timerlat histogram

  # Time unit is microseconds (us)

  # Duration:   0 00:10:00

Documentation/tools/rtla/rtla-timerlat-top.rst

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.. include:: common_timerlat_aa.rst



**--aa-only** *us*



        Set stop tracing conditions and run without collecting and displaying statistics.

        Print the auto-analysis if the system hits the stop tracing condition. This option

        is useful to reduce rtla timerlat CPU, enabling the debug without the overhead of

        collecting the statistics.



EXAMPLE

=======