We describe a new algorithm, called Quasi-Partitioned Scheduling (QPS), capable of scheduling any feasible system composed of independent implicit-deadline sporadic tasks on identical processors. QPS partitions the system tasks into subsets, each of which is either scheduled by EDF on a single processor or by a set of servers on two or more processors. More precisely, QPS uses an efficient scheme to switch between partitioned EDF and global-like scheduling rules in response to system load variation, providing dynamic adaptation in the system. Extensive simulation compares QPS favorably against related work, showing that it has very low preemption and migration overheads.

The MapReduce framework is being extended for domains quite different from the web applications for which it was designed, including the processing of big structured data, e.g., scientific and financial data. Previous work using MapReduce to process scientific data ignores existing structure when assigning intermediate data and scheduling tasks. In this paper, we present a method for incorporating knowledge of the structure of scientific data and executing query into the MapReduce communication model. Built in SciHadoop, a version of the Hadoop MapReduce framework for scientific data, SIDR intelligently partitions and routes intermediate data, allowing it to: remove Hadoop's global barrier and execute Reduce tasks prior to all Map tasks completing; minimize intermediate key skew; and produce early, correct results. SIDR executes queries up to 2.5 times faster than Hadoop and 37% faster than SciHadoop; produces initial results with only 6% of the query completed; and produces dense, contiguous output.

Optimal multiprocessor real-time schedulers incur significant overhead for preemptions and migrations. We present RUN, an efficient scheduler that reduces the multiprocessor problem to a series of uniprocessor problems. RUN significantly outperforms existing optimal algorithms with an upper bound of O(log m) average preemptions per job on m processors (≤ than 3 per job in all of our simulated task sets) and reduces to Partitioned EDF whenever a proper partitioning is found.

We consider the problem of optimal real-time scheduling of periodic and sporadic tasks for identical multiprocessors. A number of recent papers have used the notions of fluid scheduling and deadline partitioning to guarantee optimality and improve performance. In this paper, we develop a unifying theory with the DP-FAIR scheduling policy and examine how it overcomes problems faced by greedy scheduling algorithms. We then present a simple DP-FAIR scheduling algorithm, DP-WRAP, which serves as a least common ancestor to many recent algorithms. We also show how to extend DP-FAIR to the scheduling of sporadic tasks with arbitrary deadlines.