In large-scale computation such as scientific-technological computation using a computer system, parallel computation is performed using a plurality of computers. The computer system capable of performing parallel computation is referred to as a parallel computer system.
A large-scale parallel computer system includes many computers that perform parallel computation, and a management computer. The management computer manages jobs to be executed by the computers. For example, the management computer performs scheduling of the jobs inputted from a terminal device, and causes one or more computers to execute a job at an execution-scheduled start time.
The computers of the parallel computer system are interconnected, for example, via a mesh- or torus-type network topology. When the plurality of computers execute jobs in parallel in the mesh- or torus-connected network, a submesh including only free node is defined in the network. In a three-dimensional network, the submesh is a cubic area in the network. In a two-dimensional network, the submesh is a rectangular area in the network. Causing computers in the submesh to execute a job allows interference of communication between computers that process different jobs to be suppressed.
When a plurality of computers that execute parallel jobs are limited to computers in one submesh, interference of communication may be reliably suppressed. However, a group of free computers that are not allocated to any job are dispersed, thereby causing fragmentation of computer group. The fragmentation of computer group means that it is difficult to set a submesh including enough free computers allocated to a new job, and thus, the computer group is not allocated to the new job. The fragmentation of computer group contributes to lower the operating ratio of the entire parallel computer system.
One of techniques of the above job scheduling is job scheduling taking on migration into account.
A related technique is disclosed, for example, in Japanese Laid-open Patent Publication No. 2002-7364.