Experimental Physics and
Industrial Control System

Eric Norum <[email protected]> · Wed, 27 Nov 2002 18:51:05 -0600

On Wednesday, November 27, 2002, at 03:17  PM, Till Straumann wrote:

Again: IMO, EPICS should have the _full_ range of OS priorities

available.

Part of the job of porting EPICS to a particular OS would be assigning

the actual values of basic EPICS priorities (like

epicsThreadPriorityIocsh, epicsThreadPriorityBaseMin,

epicsThreadPriorityBaseMax...).

It's absurd: I use EPICS on a real-time OS but have no access to the

priorities needed to get real-time performance when I use the

epicsThread API ;-)

Is 100 levels not enough? If priorities 91-99 were reserved for

application threads only would it not be possible to do what you need?

I think that it's better to coerce other system tasks into the EPICS

range if appropriate since it makes moving a given EPICS application

from one processor to another so much easier.

I think that the 'base max' (I'm still hoping that someone can come up

with a good name for this) priority level (90, right???) should be

added to epicsThread.h. Once it's there I'll set up the RTEMS

initialization to run the iocsh at that priority.

As well, if there's no opposition, I'm going to change the default

priority for the RTEMS network and error logging daemons to be one less

than epicsThreadPriorityScanLow, the lowest-priority scan task.

I think that this may be the last chance to make these changes without

a lot of input from the entire EPICS community.

--
Eric Norum <[email protected]>
Department of Electrical Engineering
University of Saskatchewan
Saskatoon, Canada.
Phone: (306) 966-5394   FAX:   (306) 966-5407

Experimental Physics and Industrial Control System

Experimental Physics and
Industrial Control System