z/VM: CP Commands and Utilities Reference - z/VM - IBM

QUERY SCMEASURE
QUERY SCMEASURE
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Query
Authorization
Purpose
Operands
SCMeasure
Usage Notes
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rdev
rdev1-rdev2
Privilege Class: B, E
Use QUERY SCMEASURE to display whether subchannel measurement data is
being collected for a specific device or range of devices.
rdev
rdev1-rdev2
is the real device number (or numbers) of the device for which you want to
display subchannel measuring status. The variable rdev must be a hexadecimal
number between X'0000' and X'FFFF'. You can specify a single device address,
a range of device addresses, or any combination thereof.
1. Subchannel measurement blocks (SCMBKs) are used to accumulate data about
a subchannel, such as rate and utilization information. This subchannel
measurement data, which CP Monitor collects in various monitor records, can
be useful for analyzing the I/O performance characteristics of a real device.
2. To enable or disable the collecting of subchannel measurement data for one or
more devices, use the SET SCMEASURE command (page 1377).
3. When a device is first initialized, the default is to enable it for collecting
subchannel measurements. To change this initial default, use the
SCMEASURED or NOTSCMEASURED operands of the DEVICES statement in
the system configuration file. For more information about the DEVICES
statement, see the z/VM: CP Planning and Administration book.
4. Error messages produced for this command may vary depending on how the
device was specified on the command line.
When a single device is listed on the command line, an error will be reported if
there is no query information available for the single device. For example:
query scmeasure 102
Device 0102 does not exist
Ready(00040);
984 z/VM: CP Commands and Utilities Reference
When a range of devices is listed on the command line, only devices that have
query information available are shown. Error messages are not issued for
individual devices within the range. For example:
query scmeasure 100-105
Subchannel measuring for device 103 is on
Subchannel measuring for device 104 is off
Ready;
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