[Ace-users] Re: [ciao-users] Priority assigment in CIAO 0.5.9

Jaiganesh Balasubramanian jai at dre.vanderbilt.edu
Thu Jul 12 09:53:46 CDT 2007

Hi Santos,

> I'd like to know if there are any features in CIAO to assign the
> priority of facet operations and/or events. Is there already any
> integration with the scheduling service? If any of the answers is yes, I
> would appreciate if you point me some sources to read.

I would answer this in multiple parts.

1. Assume 3 components A, B, and C. Assume a facet provided by component
A. If we have a receptacle from component B and receptacle from component
C make a call on the facet on component A, and if they use
CLIENT_PROPAGATED priority model, then the facet in component A will work
on the requests from receptacles in component B and component C in
different priorities.

2. The above will work if components B and components C want to make calls
on component A using supported interfaces, and use the CLIENT_PROPAGATED
priority model.

Essentially, we have had a case, where the supported interfaces, and the
different facets of a component reply with different priorities using the
CLIENT_PROPAGATED priority model.

3. However, the same cannot be duplicated with SERVER_DECLARED priority
model. This is because of the way SERVER_DECLARED priority model is
implemented by attaching policies on the POA. Right now, CIAO does not
support assigning different policies for the component instances and their
facets. So we cannot have the component instances and their facets reply
with different priorities when using the SERVER_DECLARED priority model.

However, the good news is we are going to work in changing this in the
next releases, and soon we should be able to do the following:

1. Have the component instances and their facets reply with dfferent
priorities while using both the CLIENT_PROPAGATED and SERVER_DECLARED
priority models.

Please let us know, if you have any more questions on this.


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