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SUMMARYA 'standard task graph set' is proposed for fair evaluation of multiprocessor scheduling algorithms. Developers of multiprocessor scheduling algorithms usually evaluate them using randomly generated task graphs. This makes it di cult to compare the performance of algorithms developed in di erent research groups. To make it possible to evaluate algorithms under the same conditions so that their performances can be compared fairly, this paper proposes a standard task graph set covering many of the proposed task graph generation methods. This paper also evaluates as examples two heuristic algorithms (CP and CP=MISF), a practical sequential optimization algorithm (DF=IHS), and a practical parallel optimization algorithm (PDF=IHS) using the proposed standard task graph set. This set is available at

This paper describes practical optimization/approximation algorithms for scheduling a set of partially ordered computational tasks with different processing times onto a multiprocessor system so that the schedule length is minimized. Since this problem belongs to the class of “strong” NP hard problems, we must eliminate the possibility of constructing not only pseudopolynomial time optimization algorithms, but also fully polynomial time approximation schemes unless P = NP. This paper proposes a heuristic algorithm CP/MISF (Critical Path/Most Immediate Successors First) and an optimization/approximation algorithm DF/IHS (Depth First/ Implicit Heuristic Search). DF/IHS is an excellent scheduling method which can reduce markedly the space complexity and average computation time by combining the branch‐and‐bound method with CP/MISF; it allows us to solve very large‐scale problems with a few hundred tasks.

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Abstract. This paper evaluates the performance of job scheduling schemes for pure space sharing among rigid jobs. Conventional job scheduling schemes for the pure space sharing among rigid jobs have been achieved by First Come First Served (FCFS). However, FCFS has a drawback such that it can not utilize processors efficiently. This paper evaluates the performance of job scheduling schemes that are proposed to alleviate the drawback of FCFS by simulation, performance analysis and experiments on a real multiprocessor system. The results showed that Fit Processors First Served (FPFS), which searches the job queue and positively dispatches jobs that fit idle processors, was more effective and more practical than others.