[kepler-dev] directors in Kepler

Timothy McPhillips tmcphillips at mac.com
Tue Jan 8 11:46:40 PST 2008


Hi Dan,

I just read through the "Directors in Kepler" page on the Kepler wiki  
(http://www.kepler-project.org/Wiki.jsp?page=DirectorsInKepler), and  
have   a couple questions.

First, the image DirectorChoice.gif doesn't seem to display in  
Firefox or Safari.  Could it be corrupted? I'm eager to see this  
figure.  It would be very nice to have chart showing what general  
workflow-design situations different directors support well.

Second, the document states that PN workflows "can be very  
inefficient because the Director needs to keep going through the  
actors looking for ones that have sufficient data to fire."  My  
assumption was that the PN director sets each actor running in its  
own thread, with the blocking of get() operations on empty input  
channels enabling the Java thread scheduler to do the work of  
ordering actor invocations, and with actors communicating directly  
via FIFOs without assistance from the director.  Have you looked more  
deeply into this?

Thanks!

Tim



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