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[tracecompass-dev] lttng-ust custom latency views?

Hello TraceCompass experts,

I have instrumented my embedded application with lttng-ust, adding 4 tracepoints without arguments (a1, a2, a3, a4). My app is running on a Linux 3.14.70 ARM board, and I'm using lttng 2.6.0 "Gaia". I'm uploading the data to an Ubuntu host. On the host, I can run babeltrace to get the raw tracing data.

Now I'd like to get some statistics about the time my app takes between a1->a2, a2->a3, etc. I'd like to see the min/max, navigate to the min/max, graph latency over time and see a histogram of latency distribution. Similar to the System Call Latency Views in Trace Compass.

I was hoping that I could write such an analysis in Python, deriving from the lttng-analyses. So I've tried that on a Kernel trace on my ARM board first (lttng-analyses-record , version v0.6.1). But uploading the Kernel trace to the host and running a simple command like "lttng-cputop-mi mytrace" just thinks a while and then prints
{"error-message": "Error: Cannot run analysis: 'State' object has no attribute 'tracer_version'"}

My questions:
  • Is it a reasonable approach writing an external analysis for my lttng-ust in Python? Or is there any simpler / better way getting the latency statistics that I want?
  • Any clue what I could do to get lttng-analyses to work in my environment?
  • How could I move on getting the latency statistics?
Thanks a lot for any hints!

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