This thread has moved to the question of utilization, discussed by Mark Hahn, Gus Correa and Håkon Bugge. In my previous job most people developed code, though test runs could run for days and use as many as 64 cores. It was convenient for most people to have immediate access due to the excess computation capacity whereas some people in top management wanted maximum utilization.
I was at a parallel computing workshop where other people described the contrast between their needs and the goals of their computer centers. The computer centers wanted maximum utilization whereas the spare capacity of the various clusters in the labs were especially useful for the researchers. They could bring to bear the computational power of their informally administered clusters for special tasks such as when a huge block of data needed to be analyzed in nearly realtime to see if an experiment of limited duration was going well. When most work involves code development, waiting for jobs in a batch queue means that the human resources are not being used efficiently. Of course, maximum utilization of computer resources is necessary for production code, I just want to emphasize the wide range of needs. I would like to add that maximum utilization and fast turn- around are contradictory goals, it would seem to me based on the following reasoning. Consider packing a truck with boxes where the heigth of the boxes represents the number of cores and the width of the boxes represents the time of execution (leaving aside third spatial dimension). To most efficiently solve the packing problem we would like to have all boxes visible on the loading dock before we start packing. On the other hand, if boxes arrive a few at a time and we must put the boxes into the truck as they arrive (low queue wait time) then the packing will not be efficient. Moreover, as a very rough estimate, the size of the box defines the scale of the problem, specifically, if the average running time is 4 hours, then to have efficient "packing" the time spent waiting in a queue must on the order of at least 4 and more likely 8 hours in order to have enough requests visible to be able to find an efficient solution to the scheduling problem. Best regards, Alan -- Alan Scheinine 5010 Mancuso Lane, Apt. 621 Baton Rouge, LA 70809 Email: [EMAIL PROTECTED] Office phone: 225 578 0294 Mobile phone USA: 225 288 4176 [+1 225 288 4176] _______________________________________________ Beowulf mailing list, Beowulf@beowulf.org To change your subscription (digest mode or unsubscribe) visit http://www.beowulf.org/mailman/listinfo/beowulf
