Experimental Physics and
Industrial Control System

Andrew Johnson <[email protected]> · Fri, 15 Apr 2011 10:07:26 -0500

Hi Lorna,

On Friday 15 April 2011 02:34:53 [email protected] wrote:
> 
> We developed a client based on libca (EPICS Base 3.14.9), which will
> create it's own worker thread on construction. But we found it working
> strangely on vxWorks (ppc-603). Whenever a second EPICS client is created
> (meaning there are now 2 EPICS worker threads on vxWorks), the CPU usage
> became 100%.
> 
> From the profile, we found the ca_pend_event is consuming lots of the CPU.
> 
> Meanwhile, it seems epicsMutex is failing to do the lock for the second
> EPICS client??

EPICS should work fine on your hardware and OS combination, this is probably 
an application programming issue.

Are these two threads sharing a single CA client context?  Hopefully Jeff Hill 
will respond here too, but you might want to read this and the following 
sections of the CA Reference Manual for some ideas:
  http://www.aps.anl.gov/epics/base/R3-14/12-docs/CAref.html#Thread
In particular if you're experienced in writing multi-threaded code you might 
want to use ca_enable_preemptive_callback mode and completely avoid having to 
call ca_pend_event() in your code.

- Andrew
-- 
An error is only a mistake if you don't learn from it.
When you learn something from it, it becomes a lesson.

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System