Delay-Cost Scheduling for Multithreaded, Multicore Machines

We outline a generalization of the delay-cost objective function approach employed in the IBM System I scheduler to systems with possibly large numbers of multithreaded machines. We concentrate on hypervisor scheduling of guest operating systems, although some discussion is included of OS scheduling in such systems, and the results may be applicable in larger contexts, such as management of computer installations. Two main differences between the issues treated here and current schedulers are a) the inclusion of coscheduling of multiple logical processors associated with a guest OS, and b) the inclusion of multiple ways to satisfy a request for logical processing resources, with different utilizations of hardware threads and electrical power as a function of the application. A generalized delay-cost objective function is described, as well as two versions of, or approaches to optimality, respectively the maximization of the objective function, and maximization of this function subject to a fairness criterion. Allocation of resources to jobs is done in two phases: first an amount is determined, and secondly this is matched with physical entities. The report includes a development and discussion of the generalized delay-cost function, the algorithms used in scheduling, as well as a variety of experimental results which suggest that the overall approach is reasonable, since both the speed of execution, as well as the system power utilization, can depend on the number and identity of the system resources utilized by specific applications.

By: Peter A. Franaszek; Dan E. Poff

Published in: RC24167 in 2007

LIMITED DISTRIBUTION NOTICE:

This Research Report is available. This report has been submitted for publication outside of IBM and will probably be copyrighted if accepted for publication. It has been issued as a Research Report for early dissemination of its contents. In view of the transfer of copyright to the outside publisher, its distribution outside of IBM prior to publication should be limited to peer communications and specific requests. After outside publication, requests should be filled only by reprints or legally obtained copies of the article (e.g., payment of royalties). I have read and understand this notice and am a member of the scientific community outside or inside of IBM seeking a single copy only.

rc24167.pdf

Questions about this service can be mailed to reports@us.ibm.com .