Skip to main content

IBM Systems  >   System z  >   z/VM  >  

Contents | Previous | Next

Performance Management

These changes affect the performance management of z/VM and TCP/IP VM.

  • Monitor Enhancements
  • CP I/O Priority Queueing
  • Virtual Machine Resource Manager
  • Effects on Accounting Data
  • VM Performance Products

Monitor Enhancements

There were three major changes to the monitor data for z/VM 4.3.0. The first two changes were to include additional system configuration information and also information on the hardware I/O processors. These changes were specifically made to improve the capability of the monitor. The third change was the addition of data in support of the new I/O Priority Queuing function. As a result of these three changes, there are two new monitor records and several changed records. The detailed monitor record layouts are found on our control blocks page.

When VM runs on LPAR, second level on another VM system, or in a combination of LPAR and second level, it is often valuable to know the configuration of the underlying hypervisor. In z/VM 4.3.0, CP uses the STSI (Store System Information) instruction to gather applicable information about the physical hardware, the LPAR configuration, and the VM first level system. This additional information can be found in Domain 0 Record 15 (Logical CPU Utilization Data) and Domain 0 Record 19 (System Data).

Many of the current IBM zSeries servers have I/O processors that handle various I/O processing tasks. These are sometimes referred to as System Assist Processors. As more function is implemented in these extra processors, there is value in knowing the utilization of the processors. Monitor now collects that information and it can be found in the new Domain 5 Record 8 (I/O Processor Utilization). A zSeries server may have more than one I/O processor. A separate record is created for each I/O processor.

Support was also added in z/VM 4.3.0 to exploit I/O priority queuing. Information was added to monitor on the system settings and user settings. Record Domain 0 Record 8 (User Data) includes some system settings. The user information was added to Domain 4 Record 3 (User Activity Data). Since these settings can be changed by CP commands or the HMC for system level, Domain 2 Record 11 (I/O Priority Changes) was created to track these events.

CP I/O Priority Queueing

I/O management facilities have been added that enable z/VM to exploit the hardware I/O Priority Queueing facility to prioritize guest and host I/O operations. A virtual equivalent of the hardware facility is provided, allowing virtual machines running guest operating systems such as z/OS that exploit I/O Priority Queueing to determine the priority of their I/O operations within bounds defined by a new CP command. z/VM will automatically set a priority for I/O operations initiated by virtual machines that do not exploit this function. The IOPRIORITY directory control statement or the SET IOPRIORITY CP command can be used to set a virtual machine's I/O priority. For more information see z/VM: CP Planning and Adminstration and z/VM: CP Command and Utility Reference.

Virtual Machine Resource Manager

z/VM 4.3.0 introduces a new function, called the Virtual Machine Resource Manager, that can be used to dynamically tune the VM system so that it strives to achieve predetermined performance goals for different workloads (groups of virtual machines) running on the system. For further information, refer to the "VMRM SVM Tuning Parameters" chapter in the z/VM: Performance manual.

Effects on Accounting Data

None of the z/VM 4.3.0 performance changes are expected to have a significant effect on the values reported in the virtual machine resource usage accounting record.

z/VM 4.3.0 introduces a new accounting record (record type C) that quantifies virtual network traffic (bytes sent and received) for each virtual machine. The following virtual networks are supported: VM Guest LAN, virtual CTC, IUCV, and APPC. For further information, see z/VM: CP Planning and Adminstration.

VM Performance Products

This section contains information on the support for z/VM 4.3.0 provided by VMPRF, RTM, FCON/ESA, and VMPAF.

VMPRF support for z/VM 4.3.0 is provided by VMPRF Function Level 4.1.0, which is a preinstalled, priced feature of z/VM 4.3.0. The latest service is recommended, which includes new system configuration, LPAR configuration, and I/O processor reports:

  • SYSTEM_CONFIG_BY_TIME (PRF118) provides information about the CPU configuration of the monitored VM system. If the VM system being monitored is being run second level (or third level, etc.), the CPU configuration of both the first-level VM system and the monitored VM system are provided.

    For VM systems running in an LPAR, LPAR_CONFIG_BY_TIME (PRF119) provides processor configuration information for that LPAR.

    IOPROCESSORS_BY_TIME (PRF120) provides processor utilization and I/O activity data for each of the I/O processors in the real processor configuration. Summary (PRF121) and trend (PRF122) records can also be produced for this data.

VMPRF 4.1.0 can also be used to reduce CP monitor data obtained from any supported VM release.

RTM support for z/VM 4.3.0 is provided by Real Time Monitor Function Level 4.1.0. As with VMPRF, RTM is a preinstalled, priced feature of z/VM 4.3.0. The latest service is pre-installed on z/VM 4.3.0 and is required.

To run FCON/ESA on any level of z/VM, FCON/ESA Version 3.2.02 or higher is required. Version 3.2.04 of the program also implements some z/VM 4.3.0 specific new monitor data; this is the recommended minimum level for operation with z/VM 4.3.0. The program runs on z/VM systems in both 31-bit and 64-bit mode and on any previous VM/ESA release.

Performance Analysis Facility/VM 1.1.3 (VMPAF) will run on z/VM 4.3.0 with the same support as z/VM 4.2.0.

Contents | Previous | Next