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Common Timerlat Options

Documentation/tools/rtla/common_timerlat_options.rst

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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.

-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.

-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.