Experimental Physics and
Industrial Control System

Ben Franksen <[email protected]> · Sun, 14 Nov 2010 22:47:26 +0100

Hi Jeff

I have two technical CA (client) questions.

(1) The sequencer currently employs an "auxiliary task" which performs 
no work other than calling

  ca_pend_event(10.0)

in an endless loop. Note that the context is created with 
ca_enable_preemptive_callback. 

I would be glad if I could get rid of this extra task, as I believe it 
is not necessary, but before I throw it out I'd rather make sure that 
there are no unwanted side-effects. Could such a task perhaps improve 
latency in certain situations? A comment in the code says this allows 
for connect/disconnect event processing, and it gets started with a 
slightly higher priority than the regular sequencer tasks. It is quite 
possible that the comment is out-dated, or just plain wrong.

(2) If I create a context (with ca_enable_preemptive_callback) in one 
task, then attach to this context in another task, then delete the 
first task without destroying the context. Does the second one continue 
to work with the same context? In other words, is the task that created 
the context in any way "privileged" over tasks that merely attach to an 
existing context? I think not, but I want to be sure.

Cheers
Ben
-- 
"Never confuse what is natural with what is habitual."
                                   -- attributed to Mahatma Gandhi

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System