Patent ID: 8112750

Claim:
A computer system comprising: a plurality of physical CPUs; a plurality of LPARs to each of which any of said physical CPUs is allocated and which execute programs under their corresponding quest OSes; management means that manages a plurality of said LPARs; a quest OS monitoring unit capable of grasping the states of the quest OSes running on said LPARs; a dispatcher unit that allocates one of said physical CPUs to shared processing requested by said management means having a higher priority than the processing of said LPARs, wherein said dispatcher unit checks the results of monitoring conducted by said guest OS monitoring unit and, based on the results, gives priority of allocation to the one of said physical CPUs that runs one of said LPARs in idle state; a set of dispatch priority tables corresponding to said physical CPUs that manage priority among shared processing requested by said management means and processing other than the shared processing, wherein, upon completion of execution of a part of the shared processing, the contents of the member of said set of dispatch priority tables corresponding to the one of said physical CPUs upon which said part of the shared processing has been executed are updated; and a table updating unit that updates the contents of said set of dispatch priority tables, wherein, upon completion of execution of a part of the shared processing, said table updating unit temporarily lowers the priority of the shared processing below that of the LPARs in idle state, thereby preventing the shared processing from monopolizing any of said physical CPUs and thus from holding up the processing of the LPAR running thereupon.