System CPU Utilization attributes

The System CPU Utilization Attribute Group provides information about CPU usage for the system. In an LPAR environment, this group also provides partition management statistics.

Note: All the percentage calculations in this workspace are unnormalized values. If an address space uses more than a single processor worth of CPU, the percentage calculation may exceed 100%. The simple TCB % is a likely candidate for exhibiting this, since its denominator is only about 2.3 seconds.

4 Hour MSUs Four-hour rolling average value of the millions of service units (MSUs) per hour. The value is updated every five minutes. It is the average of the previous 48 5-minute samples, which in turn are the average of 30 samples, taken every 10 secs. To avoid capping during system bringup (IPL), the calculation of the 4-hour rolling average assumes that the system has run for four hours without load, so for the first four hours after IPL the rolling average is not valid. Valid value is an integer in the range 0 to 2147483647.

Note: Data for this attribute is available only if you have opted to use a defined capacity limit, otherwise Not available is displayed.

Average CPU Percent The percentage of time that all processors available in this z/OS system were busy dispatching work. If an address space uses more than a single processor worth of CPU, the percentage may exceed 100%.

Average IFA Percent Average percentage of time the system consumes zSeries Application Assist Processor (zAAP) resources across all zAAPs configured to this LPAR. If an address space uses more than a single processor worth of CPU, the percentage may exceed 100%.

Average IFA Percent on CP Average percentage of time the system consumes regular processor resource executing zSeries Application Assist Processor (zAAP) work across all regular processors configured to this logical partition (LPAR). If an address space uses more than a single processor's worth of CPU, the percentage may exceed 100%.

Average Unused Group MSUs The number of MSUs that were available to the LPAR Group over the Rolling Average 4-hour period, but were not used. If the value is zero or negative, the LPAR is subject to LPAR Group Capping. If this capping is in effect, the previous Group LPAR MSU Limit can vary between the LPAR Group Entitled Minimum service and the Group Capacity Limit.

Average zIIP Percent Average percentage of System z9 Integrated Information Processor (zIIP) time the system consumed for all zIIPs configured to this LPAR.

Average zIIP Percent on CP Average percentage of regular processor time the system consumes performing work eligible for System z9 Integrated Information Processor work for all regular processors configured to this LPAR.

CPU Flag A flag that indicates how the Average CPU Percent value is calculated. Valid values can be:

RMF As reported by Resource Management Facility (RMF), this value is represented as a running average for this partition over the RMF interval.
Native This value applies to systems running in native mode or in PR/SM or Amdahl Multiple domain Facility (MDF) environments, and is based on hardware timers. It is calculated by adding TCB, SRB, and z/OS overhead times.

CPUs Offline A string of CPU sequence numbers, separated by commas, that identifies those processors that are offline to this LPAR. Valid value is a 32-byte character string.

CPUs Online A string of processor sequence numbers, separated by commas, that identifies those processors that are online to this LPAR. Valid value is a 32-byte character string.

Group LPAR MSU Limit The MSU limit enforced by the LPAR Group. This limit varies between the LPAR's entitled capacity and the LPAR group capacity. When a defined capacity is specified for the LPAR, this value never exceeds that limit. If no defined capacity is specified for the LPAR, the limit can be as high as the LPAR group limit. If the LPAR is not in an LPAR Group, this value is displayed as Unavailable.

HiperDispatch Management Status of the HiperDispatch feature. The possible values are: On, Off, and Unavailable.

IFA Crossover Indicates whether IFA crossover of IFA work to regular processors is allowed (Yes) or not allowed (No).

IFA Honor Priority Indicates whether IFA work that has crossed over to a regular processor has its dispatch priority honored (Yes) or not (No).

IFA Relative Processor Speed Speed of IFAs relative to regular processors. Expressed as a ratio in the format nn .nn :1.

IFAs Offline IFAs offline to this LPAR, as a string of comma-delimited hexadecimal 2-digit processor IDs.

IFAs Online IFAs online to this LPAR as a string of comma-delimited hexadecimal 2-digit processor IDs.

LPAR Group Capacity Limit The LPAR Group Capacity Limit in Millions of Service Units per Hour. Capping of an LPAR Group is based on the 4-hour Rolling Average MSUs consumed by all the member LPARs of the LPAR Group.

LPAR Group Name The name of the LPAR Group, from 1 to 8 characters.

Managed System The z/OS operating system in your enterprise that is being monitored by an OMEGAMON XE on z/OS monitoring agent. Valid value is a character string with a maximum length of 32 bytes.

MVS Overhead The CPU utilization percentage that is not attributable to any user or address space. It is calculated as the difference between the total software utilization times and the total hardware time ((TCB + SRB)-CPU) over the last reporting interval. Valid value is a 4-byte integer.

Partition LCPD% In an LPAR environment, the percentage of time on average that a logical processor was dispatched in the logical partition during the interval.

This value is based on dispatch time, not CPU busy time. The value is calculated by dividing dispatch time by elapsed time and then dividing that product by the number of logical processors. Thus, if an LPAR has been defined as having two logical processors and the sum of their dispatch times was 90 seconds over a 60 second interval, the logical CPU percent for the partition would be (90 seconds / 60 seconds) / 2 which equals 75%.

When the number of logical processors assigned to a partition is the same as the number of physical processors, the partition's physical and logical CPU utilization should be the same.

Partition Overhead% In an LPAR environment, the percentage of time the system spends managing a logical partition. This column is valid for systems at z/OS SP4.2 or later. The value is calculated as the difference between the total software times (TCB and SRB) and the total hardware time (CPU) over the last reporting interval. Typically, z/OS overhead increases as workloads make greater demands on resources. Valid value is a 4-byte integer in the range 0 to 100.

In a complex with more than one CPU, z/OS overhead can be computed based on the number of processors, or normalized to a maximum of 100%.

Partition PCPD% In an LPAR environment, the percentage of time on average that a physical processor was dispatched in the logical partition during the interval. This value is based on dispatch time, not CPU busy time.

The value is calculated by dividing dispatch time by elapsed time and then dividing that product by the number of physical processors in the LPAR. Thus, if an LPAR has been defined as having four physical processors and the sum of their dispatch times was 120 seconds over a 60 second interval, the physical CPU percent for the partition would be (120 seconds / 60 seconds) / 4 which equals 50%.

When the number of logical processors assigned to a partition is the same as the number of physical processors, the partition's physical and logical CPU utilization should be the same.

Percent LPAR MSU Capacity Percentage of the Entitled or Defined Capacity MSUs of this LPAR, to 1 decimal place. If no Defined Capacity is specified for the LPAR, the Entitled MSUs effectively cap the maximum service an LPAR can consume. The Entitled value is based on the number of logical standard CPs configured to the LPAR, including any that are on standby. This number, multiplied by the MSU rating of a single physical standard CP, sets the Entitled service. If LPAR Group Capping is in effect for this LPAR, the Group LPAR MSU Limit establishes the maximum service that the LPAR can consume.

Physical CPU Count A count of the physical CPUs online to this LPAR. Valid value is a 4-byte integer.

RMF LPAR CPU Percent Average system CPU percentage as seen by the LPAR hosting the z/OS system, calculated over the most recent RMF interval. The first RMF interval after the agent is started contains partial values. Valid value is an integer in the range 0.0 to 100.0. If RMF is not active, this value will be zero. “NoRMF” indicates that this value is not available because the RMF API (ERBSMFI) is not active. “NoStorage” indicates that this value is not available because the CMS address space did not have sufficient storage for the RMF API answer area.

Note: The initial display will contain zeros for the RMF LPAR CPU Percent attribute. It is most likely that the collection agent will be started somewhere in the middle of an already running RMF interval. Therefore, at the completion of the first RMF interval after the collection agent was started, these attributes will contain partial values. Only after completion of the first full RMF interval will these attributes display complete and correct values. If Resource Measurement Facility (RMF) is not started, the value for this attribute will be 0.0.

RMF MVS CPU Percent Average system CPU percentage as seen by z/OS, calculated over the most recent RMF interval. If RMF is not active, this value will be zero. The first RMF interval after the agent is started contains partial values. Valid value is an integer in the range 0.0 to 100.0. “NoRMF” indicates that this value is not available because the RMF API (ERBSMFI) is not active. “NoStorage” indicates that this value is not available because the CMS address space did not have sufficient storage for the RMF API answer area.

Note: The initial display will contain zeros for the RMF MVS CPU Percent attribute.  It is most likely that the collection agent will be started somewhere in the middle of an already running RMF interval. Therefore, at the completion of the first RMF interval after the collection agent was started, these attributes will contain partial values. Only after completion of the first full RMF interval will these attributes display complete and correct values. If Resource Measurement Facility (RMF) is not started, the value for this attribute will be 0.0.

Total Enclave Percent The percentage of total CPU time spent doing enclave work. If an address space uses more than a single processor's worth of CPU, the percentage may exceed 100%.

Total SRB% The percentage of total CPU time spent doing SRB work. If an address space uses more than a single processor's worth of CPU, the percentage may exceed 100%.

Total TCB% The percentage of total CPU time spent doing TCB work. If an address space uses more than a single processor's worth of CPU, the percentage may exceed 100%.

Undispatched Tasks The number of tasks or address spaces that have not been dispatched by the SRM due to constraints. Valid value is a 4-byte integer.

WLM Mode The workload manager mode. Valid values are Goal or Compatibility.

zIIP Honor Priority Indicates whether System z9 Integrated Information Processor work that has crossed over to a regular processor has its dispatch priority honored (Yes) or not (No).

zIIP Relative Processor Speed Speed of System z9 Integrated Information Processors relative to regular processors. Expressed as a ratio in the format nn.nn:1.

zIIPs Offline System z9 Integrated Information Processors offline to this LPAR, as a string of comma-delimited hexadecimal 2-digit processor IDs.

zIIPs Online System z9 Integrated Information Processors online to this LPAR, as a string of comma-delimited hexadecimal 2-digit processor IDs.