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If you want to ...
Then use this command ...
Control the
SET SHARE
fraction of system
Example: By using these commands, you are establishing the fraction of system resources to
resources a virtual
which each virtual machine is entitled.
machine receives.
cp set share linux0 absolute 20%
cp set share linux1 relative 100
cp set share linux2 relative 300
cp set share linux3 relative 100
Notes:
1. A virtual machine receives its proportion of any scarce resource (CPUs, real storage, or paging
I/O capability) according to its SHARE setting.
2. The SET SHARE command can be used to set target minimum and maximum values (notice
that LINUX0 has a target minimum of 20%—that means other virtual machines contend for
the remaining 80% of resources).
3. You can assign shares of system resources with the user directory SHARE statement so that
when a user logs on, that virtual machine automatically has its share established.
Designate virtual
SET QUICKDSP userid
machines that do
Example:
not wait in the
eligible list when
cp set quickdsp linux0 on
they have work to
USER LINUX0 : QUICKDSP = ON
do
Note: With this setting, virtual machines are assigned an eligible list class of E0 and are added to
the dispatch list immediately. QUICKDSP overrides the scheduler's usual resource assessment
and fitting algorithms for the target virtual machine and the virtual machine is run without
regard to its resource needs. When you use QUICKDSP, you take responsibility for resource
allocation.
Guarantee that a
SET RESERVED
certain minimum
Example:
number of guest
pages will always
cp set reserved linux01 50
be resident
means you are guaranteeing that the LINUX01 virtual machine has 50 pages always resident in
real storage.
You know you are done when system performance improves.
Related information
For advanced information about performance and the z/VM scheduler, see
v
v "VM Performance Resources" (http://www.vm.ibm.com/perf/)
v "The VM/ESA Scheduler Made Simple" (http://www.vm.ibm.com/devpages/
136
z/VM: Getting Started with Linux on System z
z/VM: Performance, SC24-6208
bitner/presentations/vmsched.html)
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