SPLPAR Characteristics Definitions

SPLPAR Terms The LoPAR Shared Processor Logical Partition option (SPLPAR) defines many terms as presented in . SPLPAR Terms Term Definition Bound Threads For virtual processor dispatches, if the hypervisor always dispatches a set of virtual threads together on a physical processor, the threads are said to be bound. This allows an operating system to make scheduling decisions based on cache affinity and work load. A change in this characteristic takes effect on the next reboot of the partition. Capacity Increment This defines the delta by which the entitled capacity of a partition can be incremented or decremented by DLPAR/WLM. The capacity increment is expressed as a percentage of a physical processor. A change in the capacity increment takes effect on the next reboot of the partition. Desired Entitled Capacity The desired entitled capacity set by the system administrator in the partition definition. The desired entitled capacity is expressed as a percentage of a physical processor. The desired entitled capacity can change without a reboot of the partition. The entitled capacity that the partition is currently using may differ from the desired entitled capacity because of WLM actions or failed system processors. Desired Memory The desired memory set by the system administrator in the partition definition. The desired memory is expressed in MB of storage. The desired memory can change without a reboot of the partition. The desired memory that the partition is currently using may differ from the desired memory because of WLM actions or because of failed system memory. Desired Number of Processors The desired number of virtual processors set by the system administrator in the partition definition. The desired number of processors can change without a reboot of the partition. The number of processors that the partition is currently using may differ from the desired number of processors because of WLM actions or because of failed system processors. Desired Variable Capacity Weight The desired variable capacity weight set by the system administrator in the partition definition. The desired variable capacity weight is a number between 0 and 255. The desired variable capacity weight can change without a reboot of the partition. The variable capacity weight that the partition is currently using may differ from the desired variable capacity because of WLM actions. Dispatch Wheel Rotation Period The duration of the hypervisor’s scheduling window. The time over which the entitled capacity of a virtual processor has to be utilized by the partition. At the start of a dispatch wheel rotation period, each virtual processor is eligible for CPU time corresponding to its entitled capacity. If the entire entitled capacity of a virtual processor is not utilized during a dispatch wheel rotation period, the unused entitled capacity is lost. The dispatch wheel rotation period is expressed as N number of time base ticks. The dispatch wheel duration of a partition with a capacity increment of 100 is 0. A change in the dispatch wheel rotation period takes effect on the next reboot of the partition. Minimum Entitled Capacity The minimum entitled capacity that is needed to power on the partition. The capacity is expressed as a percentage of a physical processor. The minimum entitled capacity is set by the system administrator in the partition definition. DLPAR cannot take the entitled capacity below the minimum entitled capacity. A change in the minimum entitled capacity takes effect on the next reboot of the partition. A partition can give up its entitled capacity to be below the minimum entitled capacity. Minimum Entitled Capacity per Virtual Processor The minimum entitled capacity that the platform requires for a virtual processor of any partition on the platform. The minimum virtual per virtual processor is enforced by the HMC in the partition definition and by the hypervisor for H_SET_PPP ( ). A change in the minimum entitled capacity per virtual processor takes effect on the next reboot of the partition. Minimum Memory The minimum amount of main store that is needed to power on the partition. Minimum memory is expressed in MB of storage. The minimum memory is set by the system administrator in the partition definition. DLPAR cannot take the partition memory below the minimum memory. A change in the minimum memory takes effect on the next reboot of the partition. A partition can always give up its memory to go below the minimum memory. Minimum Number of Processors The minimum number of virtual processors that are needed to start the partition. The minimum number of virtual processors is set by the system administrator in the partition definition. DLPAR cannot take the number of virtual processors below the minimum number of processors. A change in the minimum number of processors takes effect on the next reboot of the partition. A partition can always give up its virtual processors to go below the minimum number of processors. Maximum Entitled Capacity The maximum entitled capacity currently that can be assigned to the partition through DLPAR/WLM. The capacity is expressed as a percentage of a physical processor. The Maximum entitled capacity is set up by the system administrator in the partition definition. A change in the maximum entitled capacity maximum takes effect on the next reboot of the partition. Maximum Platform Processors The maximum number of processors that can be active on the platform. A change in the maximum platform processors takes effect on the next reboot of the partition. Dedicated Donate Mode For a partition with a capacity increment of 100, the platform uses a dedicated CPU to actualize a virtual processor of the partition. For such a partition, the platform can increase the capacity of the shared processor pool by utilizing the unused processor capacity of the partition. If the platform supports the dedicated donate function, it can be enabled by the system administrator in the partition definition. The value of this characteristic can change without a reboot of the partition. Thread A multi threaded processor may have multiple contexts executing concurrently. Each of them is called a thread. From a software viewpoint, a thread is an independent executing unit. Threads on a processor share some of the architected and unarchitected resources of a physical processor.

Key Words And Values Table defines the key words and the associated legal values that will be returned in the ASCII NULL terminated string when the parameter token value of 20 (SPLPAR characteristics) is specified on the ibm,get-system-parameter RTAS call. The key word and value is separated by an ascii equal (“=”). Each key word, value pair is delimited by an ascii comma in the string. The numerical value of the characteristic corresponding to the key word is the decimal number that corresponds to the numeric characters in the value part of the key word, value pair. SPLPAR Characteristics Characteristics Key Word Values Notes Bound Threads BoundThrds 0,1 1 Capacity Increment CapInc 1 through 100 Dispatch Wheel Rotation Period DisWheRotPer 1 through N Minimum Entitled Capacity MinEntCap 0 through N 2 Minimum Entitled Capacity per Virtual Processor MinEntCapPerVP 1 through 100 Minimum Memory MinMem 0 through N Minimum Number of Processors MinProcs 0 through N Maximum Entitled Capacity MaxEntCap 1 through N 3 Maximum Platform Processors MaxPlatProcs 1 through N Desired Entitled Capacity DesEntCap 0 through N 4 Desired Memory DesMem 0 through N 5 Desired Number of Processors DesProcs 0 through N 6 Desired Variable Capacity Weight DesVarCapWt 0 through 255 Dedicated Donate Mode DedDonMode 0,1 7

Notes: 0=Threads are not bound, 1=Threads are bound. The maximum numeric value of Minimum Entitled Capacity is the number of processors on the platform multiplied by 100. The maximum numeric value of Maximum Entitled Capacity is the number of processors on the platform multiplied by 100. The numeric value of Desired Entitled Capacity is greater or equal than the numeric value of the Minimum Entitled Capacity and less than or equal to the numeric value of the Maximum Entitled Capacity. The numeric value of Desired Memory is greater or equal than the numeric value of the Minimum Memory and less than or equal to the maximum memory set by the system administrator in the partition profile. The numeric value of Desired Number of Processors is greater or equal than the numeric value of the Minimum Number of Processors and less than or equal to the maximum number of virtual processors set by the system administrator in the partition profile. 0=Dedicated Donate Mode is disabled, 1=Dedicated Donate Mode is enabled.