Patent ID: 8423728
Filing Date: 2013-04-16
Classification: G06F

Abstract:
1. A method of scheduling jobs for a plurality of logical devices associated with physical devices, comprising: assigning a physical run count value and a physical skip count value to each of the physical devices; at each iteration, examining the physical skip count value and the physical run count value for each of the physical devices; scheduling a number of jobs up to the physical run count value for logical devices associated with a particular one of the physical devices at each iteration corresponding to the physical skip count value for the particular one of the physical devices; for at least one logical device associated with the particular one of the physical devices, assigning a logical run count value and a logical skip count value thereto, wherein the logical run count value and the logical skip count value are determined separately from the physical run count value and the physical skip count value; and scheduling a number of jobs up to the logical run count value for the at least one logical device associated with the particular one of the physical devices at each iteration corresponding to the logical skip count value for the at least one logical device, wherein scheduling a number of jobs up to the logical run count value includes examining each of a plurality of logical devices associated with the particular physical device to schedule jobs for a subset of the plurality of logical devices, and wherein scheduling jobs for the subset of the plurality of the logical devices includes: wherein at least one of the following is provided: (i) no logical skip count value and no logical run count value is associated with logical devices having only pending read jobs, or (ii) logical devices having only pending read jobs have no logical skip count value associated therewith and have a logical run count value of one.