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Performance Management

These changes affect the performance management of z/VM:

• MONDCSS and the SET RESERVED Command
• Space for MONWRITE Data
• Monitor Changes
• Command and Output Changes
• Effects on Accounting Data
• Performance Toolkit for VM Changes
• Omegamon XE Changes

MONDCSS and the SET RESERVED Command

The SET RESERVED command can be used to specify the number of pages of your monitor saved segment (MONDCSS) that should remain resident even though the system is paging. Reserved settings are not preserved across IPL, so you will need to include the SET RESERVED command for the monitor saved segment in your IPL procedure. For more information on SET RESERVED see z/VM CP Commands and Utilities Reference.

Space for MONWRITE Data

z/VM HiperDispatch emits the new D5 R16 MRPRCPUP event record every two seconds. As a result, MONWRITE files might be larger than in previous releases. Keep track of space on the MONWRITE collection disk and make adjustments as needed.

Monitor Changes

Several z/VM 6.3 enhancements affect CP monitor data. There are four new monitor records and several changed records. The detailed monitor record layouts are found on the control blocks page.

The next generation FCP adapter incorporates a "data-mover" hardware function that provides direct memory access (DMA) between the FCP adapter's SCSI interface card and memory. The data-mover function eliminates the need to store SCSI data within an interim buffer in the FCP adapter, which is typically referred to as a "store-and-forward" data transfer approach. The following monitor records are updated for this support:

z/VM HiperDispatch provides z/VM host exploitation of CPU topology information and vertical polarization for greater processor cache efficiency and reduced multi-processor effects. z/VM HiperDispatch can be used to increase the CPU performance and scalability of z/VM and guest workloads to make more efficient use of resources.

The following monitor records are added and/or updated for z/VM HiperDispatch support:

Added monitor records:

Updated monitor records:

Traditional System z HiperSockets messages are transmitted synchronously by the sending CPU, and feedback on success/failure is given immediately in the form of a condition code. However, in short-burst scenarios where more data needs to be sent than can be supported by the current number of queues, performance degrades as drivers are given busy conditions and are asked to make the decision to retry or fail. HiperSockets Completion Queues support provides a mechanism by which the hardware can buffer requests and perform them asynchronously. The following monitor records are updated for this support:

z/VM's dump capacity is increased to support real memory up to a maximum of 1 TB in size. The following monitor records have been changed:

The z/VM memory management algorithms are redesigned to enable support for real memory up to 1 TB. These enhancements are intended to improve efficiency for the over commitment of virtual to real memory for guests and to improve performance. The following monitor records are changed for this support:

Virtual Edge Port Aggregator (VEPA) is part of the emerging IEEE 802.1Qbg standardization effort and is designed to reduce the complexities associated with highly virtualized deployments such as hypervisor virtual switches bridging many virtual machines. VEPA provides the capability to take all virtual machine traffic sent by the server and send it to an adjacent network switch. This support updates the following monitor records:

VSWITCH recovery stall prevention provides additional virtual switch uplink and bridge port recovery logic to failover to another backup device when encountering a missing interrupt condition. The following monitor record is changed for this support:

To provide additional debug information for system and performance problems, z/VM 6.3 added or changed these monitor records:

Finally, it should be noted that in APAR VM65007 IBM introduced z/VM support for the zEC12 processor. This support is now available in base z/VM 6.3. Part of this work was to enhance z/VM to collect the kinds of CPU Measurement Facility counters the zEC12 emits. The D5 R13 MRPRCMFC record was not itself changed to handle the zEC12, but reduction programs will see that the MRPRCCMF record contains the zEC12's CPU MF counter version numbers if the record is from a zEC12. Existing MRPRCCMF payload carriage techniques were used to carry the zEC12's counters.

Command and Output Changes

This section cites new or changed commands or command outputs that are relevant to the task of performance management. It is not an inventory of every new or changed command.

The section does not give syntax diagrams, sample command outputs, or the like. Current copies of z/VM publications can be found in the online library.

DEDICATE: The DEDICATE command is not supported if the partition is vertical.

QUERY PROCESSORS: The output is modified to display whether a CPU is parked.

INDICATE LOAD: The output is modified to display CPU polarity. Also, the CPU utilization is now percent of a physical CPU's capacity instead of percent of time without a wait PSW loaded.

INDICATE QUEUES: The output is modified to indicate DSVBK placement.

QUERY SRM: The command is modified to display polarization, CPUPAD, EXCESSUSE, and work distributor.

SET SRM: The command is modified to set polarization, CPUPAD, EXCESSUSE, or work distributor.

SET DUMP: The command is modified to allow specification of up to 32 RDEVs.

SDINST: This new command installs the stand-alone dump facility.

DUMPLD2: The command is modified to add a new operand, DASD.

SET AGELIST: This new command controls the global aging list.

QUERY AGELIST: This new command displays information about the global aging list.

SET RESERVED: This command is modified to allow setting reserved frame amounts for an NSS or DCSS.

QUERY RESERVED: This command is modified to display new information about settings for reserved frames.

INDICATE LOAD: The output's STEAL clause is removed.

INDICATE NSS: The output is modified to display counts of instantiated pages and reserved frames.

INDICATE SPACES: The output is modified to display counts of instantiated pages.

INDICATE USER: The output is modified to display counts of instantiated pages.

SET REORDER: The command now always returns RC=6005.

QUERY REORDER: The command now always displays that reorder is off.

IPL: The command supports a new DUMP option, NSSDATA.

SET VSWITCH: The command provides a new UPLINK SWITCHOVER function.

QUERY VSWITCH: The output is modified to contain uplink switchover information.

Effects on Accounting Data

z/VM 6.3 did not add, change, or delete any accounting records.

Performance Toolkit for VM Changes

Performance Toolkit for VM has been enhanced in z/VM 6.3.

The following reports have been changed:

Performance Toolkit for VM: Changed Reports

The following reports are new:

Performance Toolkit for VM: New Reports

IBM continually improves Performance Toolkit for VM in response to customer-reported or IBM-reported defects or suggestions. In Function Level 630 the following small improvements or repairs are notable:

• SORT performance improvement.
• Added support for device groups (FCONTROL DEVGROUP).
• Added support for OSA types 6 and 7.
• FCONX $PROFILE (sample) file corrected for optimal default settings.
• Added an ability for automatic scrolling of CP messages.
• Support for more than 100 logical CPUs in a LPAR.
• Unify the rules for suffix letters to express multipliers on datums (binary/decimal scaling factor).
• Added Left/Right buttons for wide reports on the web.
• Update the sizing exec FCXSEGSZ for new OMEGAMON tables (for handling SSI and LGR data).

Omegamon XE Changes

Omegamon XE has added several new workspaces so as to expand and enrich its ability to comment on z/VM system performance. In particular, Omegamon XE now offers these additional workspaces and functions:

• CPC workspace which shows your total processor usage, by processor type
• Single System Image
• Live Guest Relocation
• Emulated FBA on SCSI (EDEV) disks
• Integration with Smart Cloud Monitoring
• Cognos Reports
• Self-defining Agents (automatic updating of your ITM infrastructure)

To support these Omegamon XE endeavors, Performance Toolkit for VM now puts additional CP Monitor data into the PERFOUT DCSS.

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