68 lines
2.6 KiB
ReStructuredText
68 lines
2.6 KiB
ReStructuredText
.. |threshold| replace:: **-a/--auto**, **-i/--irq**, or **-T/--thread**
|
|
.. |thresharg| replace:: -T
|
|
.. |tracer| replace:: timerlat
|
|
|
|
.. |actionsperf| replace::
|
|
For time-sensitive actions, it is recommended to run **rtla timerlat** with BPF
|
|
support and RT priority. Note that due to implementational limitations, actions
|
|
might be delayed up to one second after tracing is stopped if BPF mode is not
|
|
available or disabled.
|
|
|
|
**-a**, **--auto** *us*
|
|
|
|
Set the automatic trace mode. This mode sets some commonly used options
|
|
while debugging the system. It is equivalent to use **-T** *us* **-s** *us*
|
|
**-t**. By default, *timerlat* tracer uses FIFO:95 for *timerlat* threads,
|
|
thus equilavent to **-P** *f:95*.
|
|
|
|
**-p**, **--period** *us*
|
|
|
|
Set the *timerlat* tracer period in microseconds.
|
|
|
|
**-i**, **--irq** *us*
|
|
|
|
Stop trace if the *IRQ* latency is higher than the argument in us.
|
|
|
|
**-T**, **--thread** *us*
|
|
|
|
Stop trace if the *Thread* latency is higher than the argument in us.
|
|
|
|
**-s**, **--stack** *us*
|
|
|
|
Save the stack trace at the *IRQ* if a *Thread* latency is higher than the
|
|
argument in us.
|
|
|
|
**-t**, **--trace** \[*file*]
|
|
|
|
Save the stopped trace to [*file|timerlat_trace.txt*].
|
|
|
|
**--dma-latency** *us*
|
|
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.
|
|
|
|
**--deepest-idle-state** *n*
|
|
Disable idle states higher than *n* for cpus that are running timerlat threads to
|
|
reduce exit from idle latencies. If *n* is -1, all idle states are disabled.
|
|
On exit from timerlat, the idle state setting is restored to its original state
|
|
before running timerlat.
|
|
|
|
Requires rtla to be built with libcpupower.
|
|
|
|
**-k**, **--kernel-threads**
|
|
|
|
Use timerlat kernel-space threads, in contrast of **-u**.
|
|
|
|
**-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. **--user-threads** will be used unless the user specify **-k**.
|
|
|
|
**-U**, **--user-load**
|
|
|
|
Set timerlat to run without workload, waiting for the user to dispatch a per-cpu
|
|
task that waits for a new period on the tracing/osnoise/per_cpu/cpu$ID/timerlat_fd.
|
|
See linux/tools/rtla/sample/timerlat_load.py for an example of user-load code.
|