linux-stable/Documentation/tools/rtla/common_timerlat_options.rst
Daniel Bristot de Oliveira 6127383217 Documentation: Add tools/rtla timerlat -u option documentation
Add the -u/--user-thread option documentation for timerlat top/hist.

Link: https://lkml.kernel.org/r/bf727c8ccb8f50792200ae620141e047edf4af7a.1686066600.git.bristot@kernel.org

Cc: William White <chwhite@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Tested-by: Juri Lelli <juri.lelli@redhat.com>
Signed-off-by: Daniel Bristot de Oliveira <bristot@kernel.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
2023-06-13 16:43:37 -04:00

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**-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.
**--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.
**-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.