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

SET QUICKDSP
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Set
Authorization
Purpose
QUICKDsp
Operands
Usage Notes
Responses
userid
Privilege Class: A
Use SET QUICKDSP to assign a user with immediate access to system resources.
userid
is the user ID of the virtual machine to receive the QUICKDSP designation.
ON
ON
OFF
specifies that the user is to be added to the dispatch list immediately whenever
the user has work to do, without waiting in the eligible list. Users not having this
option may wait in the eligible list and be delayed for milliseconds or even
seconds before running if there is a heavy load on the system. ON is the
default.
OFF
specifies that the QUICKDSP option is to be taken away from this user. The
user can subsequently encounter delays in the eligible list just as other users
do.
1. The QUICKDSP designation is intended for selective use on virtual machines
with critical response time requirements. The scheduler always moves a
QUICKDSP user immediately into the dispatch list whenever it is ready to run,
regardless of resource requirements and current system load. Indiscriminate
use, therefore, increases response time overall and may severely affect
maintenance of system storage.
QUICKDSP is normally provided for use by selected service virtual machines
interacting with several other users, thus having stringent response time
requirements. RSCS and IUCV applications are common examples.
2. In some cases, the SET RESERVED command should be used with
QUICKDSP, especially in storage-constrained environments. A user with the
QUICKDSP attribute and reserved pages experiences little system overhead,
further improving response time.
3. The QUICKDSP designation is given to users who are being forced or logged
off from the system to expedite the logoff of those users.
Response 1:
USER userid: QUICKDSP={ON }
{OFF}
SET QUICKDSP
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Chapter 2. CP Commands 1331