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

SET SHARE
Responses
Messages
requirements can be compared. If the users are limited by the same
bottlenecked resource, a RELATIVE SHARE user with twice the SHARE of
another should run twice as fast.
3. The target maximum share is applicable only to the CPU resource.
If a target maximum share is specified, the user will not necessarily receive that
amount of scheduled CPU resource. This is because a user will only receive
more than the target minimum share for a resource when other users are not
using all of their target minimum shares.
4. When the limit option is specified alone (that is, without a share and without a
maximum share being specified), only that option is changed. The userid retains
its previous share and the maximum share is changed (if necessary) to match
the new limit option. For example, if NOLIMIT is specified, then the pre-existing
maximum share (if any), is reset to zero. Or, if LIMITHARD or LIMITSOFT is
specified and there previously was no maximum share, then the maximum
share is set equal to the user’s minimum share (with the specified ’hard’ or ’soft’
characteristic).
5. Due to the dynamics of VM systems and scheduling, the maximum share target
is not always met. The actual usage should be within five percent of the system.
The accuracy may be affected by the following:
v running guest as a virtual MP
v guest use of diagnose X'44'
v running VM second level or on LPAR
v low system utilization.
6. When setting SHARE RELATIVE on a userid that has multiple CPUs, the
minimum share that the system will assign is one per virtual CPU. For example,
if you SET SHARE MAINT RELATIVE 1 and MAINT has five virtual CPUs, the
resulting SHARE will be set to five.
Response 1:
USER userid: ABSOLUTE SHARE = nnn% [; m DEDICATED CPU[S]]
MAXIMUM SHARE = option type value
- or -
HCP07E Invalid userid - userid
HCP20E Userid missing or invalid
HCP26E Operand missing or invalid
HCP45E userid not logged on
1384 z/VM: CP Commands and Utilities Reference
USER userid: RELATIVE SHARE = nnnnn [; m DEDICATED CPU[S]]
MAXIMUM SHARE = option type value
is issued when the command completes successfully. The string m DEDICATED
CPU[S] only appears if the user has real processors dedicated to his or her virtual
CPU or CPUs.