A computer-implemented method for running computing workloads on a group of system usage entities of a mainframe computer system, each system usage entity having a static processing capacity entitlement for running a computing workload thereon, the computing workload having different portions of work corresponding to different importance levels, the method comprising: for each system usage entity, determining consumption of processing capacity by the different portions of work corresponding to different importance levels in the computing workload running thereon, the processing capacity consumption being measured in millions of service units per hour, MSUs; determining a four-hour rolling average, hereinafter 4HRA, of processing capacity consumption by each system usage entity; allocating a dynamic entitlement MSU amount for each system usage entity to be the greater of all the MSUs that the system usage entity needs to complete high importance work, and a predetermined fraction of the 4HRA of the system usage entity; and using the allocated dynamic entitlements as capping limits in conjunction with a capping tool for regulating processing capacity consumption by the system usage entities when running their respective computing workloads, wherein running the respective computing workloads includes using the allocated dynamic entitlements as capping limits below a preset maximum capacity limit, combining unused MSUs from the sum of the static entitlements, which have not been allocated toward dynamic entitlements, in an excess MSU pool; and allocating additional MSU amounts out of the excess MSU pool toward the dynamic entitlements of the system usage entities, one-by-one, in one or more iterative loops, for each system usage entity, determining a low-importance workload percentage, LIWP, as the percentage of standard CPU consumption of service class periods having low importance over the consumption of all service class periods; and determining an adjusted low-importance workload percentage, ALIWP, by adjusting the LIWP upward or downward according to a priority associated with the system usage entity, wherein allocating additional MSU amounts out of the excess MSU pool includes, in each iterative loop, beginning allocating additional MSU amounts with the system usage entity having the lowest ALIWP, proceeding to the system usage entity having the next lowest ALIWP, and ending with the system usage entity having the highest ALIWP. for each system usage entity, determining consumption of processing capacity by the different portions of work corresponding to different importance levels in the computing workload running thereon, the processing capacity consumption being measured in millions of service units per hour, MSUs; determining a four-hour rolling average, hereinafter 4HRA, of processing capacity consumption by each system usage entity; allocating a dynamic entitlement MSU amount for each system usage entity to be the greater of all the MSUs that the system usage entity needs to complete high importance work, and a predetermined fraction of the 4HRA of the system usage entity; and all the MSUs that the system usage entity needs to complete high importance work, and a predetermined fraction of the 4HRA of the system usage entity; and using the allocated dynamic entitlements as capping limits in conjunction with a capping tool for regulating processing capacity consumption by the system usage entities when running their respective computing workloads, wherein running the respective computing workloads includes using the allocated dynamic entitlements as capping limits below a preset maximum capacity limit, combining unused MSUs from the sum of the static entitlements, which have not been allocated toward dynamic entitlements, in an excess MSU pool; and allocating additional MSU amounts out of the excess MSU pool toward the dynamic entitlements of the system usage entities, one-by-one, in one or more iterative loops, for each system usage entity, determining a low-importance workload percentage, LIWP, as the percentage of standard CPU consumption of service class periods having low importance over the consumption of all service class periods; and determining an adjusted low-importance workload percentage, ALIWP, by adjusting the LIWP upward or downward according to a priority associated with the system usage entity, wherein allocating additional MSU amounts out of the excess MSU pool includes, in each iterative loop, beginning allocating additional MSU amounts with the system usage entity having the lowest ALIWP, proceeding to the system usage entity having the next lowest ALIWP, and ending with the system usage entity having the highest ALIWP.