PLEASE HELP regarding System Tap

[Stone, Joshua I]

Frank Ch. Eigler wrote:
> Looking at your script, you are doing one space-hungry and one
> time-hungry thing that may each need change.  Your npr_pktsize[] array
> will be both tall and wide -- potentially many elements, each a wide
> histogram.  That will consume lots of memory to store.  The whole
> array will also take lots of time (statements) and (buffer) space to
> print out with that unlimited foreach().  Depending on which resource
> systemtap detects as exhausted, you may get different error messages.
> For each of them, there is some sort of countermeasure.

Also, it might be helpful to find a reasonable "end-of-connection" probe point for a given connection id.  At that point you could print the accumulated data for that connection and delete it from the array.  If npr_pktsize only contains the currently active connections, you'll probably have a much better bound on the size.

Josh