[lttng-dev] workqueue tracing symbols

[Akhil Veeraghanta]

Hello,

We are trying to debug kernel work queue related issues in our system. And as such, we've turned on workqueue_queue_work, workqueue_active_work, workqueue_execute_start, workqueue_execute_end.

The tracepoint itself stores the function pointer which we can look up from /proc/kallsyms manually.

We've been struggling to do this automatically, we've tried:


  1.
Using babeltrace2 to "convert" from lttng to lttng by just editing the events in place. This doesn't work (atleast as easily) because the event iterator is const.

  2.
Loading the kallsyms file with "Configure Symbols" in trace compass doesn't work either because it doesn't know that it can look up functions in workqueue events from that file.

Converting to a text based format like chrome trace and replacing the fields works, but then we have to use chrome::tracing which isn't as powerful.

Before we go any futher modifying trace compass or writing a smarter parser, is there a way we can trace the workqueues and do the lookup properly?

  3.

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