Experimental Physics and
Industrial Control System

Benjamin Franksen <[email protected]> · Sat, 13 Apr 2013 14:42:07 +0200

Hi People

we have recently discovered some bugs in devIocStats in the vxWorks
implementation that measures the cpu load, which result in wrong results to be
displayed. I hacked away at the problem for some days and ended up with a
complete re-write. The solution considerably reduces code size and complexity,
is therefore much easier to understand and maintain, and --most importantly--
works correctly. It also contains some additional features:

* A test procedure that measures how well the initial calibration works by
doing it for a number of times and gathering statistics (min, max, avg). This
was useful to determine how long initial calibration should run (the default
is 30 clock ticks which on a mv2100 gives me a variation of less than 0.4%).

* Another test procedure (to be called from the shell) adds exactly 50% load
to the IOC (it burns cpu for one clock tick, then sleeps for one, and repeats
that in a loop for the given duration), so one can see whether the measured
cpu load increases appropriately (it does on my test machines).

* Experienced users can customize behaviour to a certain extent by changing
the values of some global variables.

One downside is that I have tested only with a pretty old version of vxWorks
(5.4.2, we do not have any more recent one here) and with mv162 and mv2100
boards. I would like to ask anyone interested whether they would be willing to
test my code with newer vxWorks versions and other hardware. I don't expect
problems but I would feel safer...

Who is currently maintaining devIocStats and how do I submit patches?

Cheers
--
Ben Franksen
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Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System