-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.