Loading a disabled PSW Loading an enabled PSW with no active 110 in process
Logging on or off.
When the virtual machine becomes executable again, it is put back on the dispatch
list in Q 1. If dropped from Q 1, the virtual machine is placed directly in the Q2 dis
patch list. If the percentage option of theSET FAVORED command is specified,
the deadline priority is calculated at queue drop time by:
current time-of-day + length of allowed processor in-queue time slice
favored percentage
User Priority
For example, if the processor in-queue time slice is 1 second, and the specified per
centage is10 percent, then the value added to the current time-of-day is 10 sec
onds. The virtual machine should receive one processor time slice (1 second) once
every10 seconds.
Note, however, that these options can impact the response times of other virtual
machines. To provide a virtual machine with both options, basic and percentage,
both forms of the command for that virtual machine must be issued. The percent
age form of theSET FAVORED command can be used to specify any number of
logged-on virtual machines.
Although theSET FAVORED command prevents specifying more than 100
% for
a particular virtual machine, nothing is done to prevent allocating more than 100% to a number of virtual machines. Where more than 1 00% has been allocated, the
favored virtual machines compete for the available resources on a pro-rata basis.
An individual virtual machine's allocation is, roughly, proportional to the percent
age allocated to it, divided by the total percentage allocated to all virtual machines.
The effect of allocating more than1000/0 of the system on interactive (Ql)
responses is unpredictable.
Note: The percentage of the processor time actually received by the favoredusc normally remains relatively close to the percentage specified in the command.
However, it is not an absolute value, and varies depending on the total load on the
system and the type of load on the system. If, for example, there are multiple vir
tual machines on the runlist that are compute bound (That is, are not queue
dropped before the end of their in-queue time slice), then the favored user may not
receive its requested percentage of the total processor time.
TheVM/SP operator can assign specific priority values to different virtual
machines. In so doing, the virtual machine with a higher priority is allocated a larg
er share of the system resources before a virtual machine with a lower priority.
User priorities are set by the following class A command:SET PRIORITY userid nn
where userid is the user's identification and nn is an integer value from 1 to 99.
The value of nn affects the user's dispatching priority in relation to other users in
the system. The priority value (nn) is one of the factors considered in the calcu
lation of the deadline priority. The deadline priority is the basis on which all virtual
machines in the system are ordered on both the eligible list and the dispatch list.
The deadline priority calculation is based on the assumption that the average or
normal (default) user priority is 64.
Performance Guidelines 31
Logging on or off.
When the virtual machine becomes executable again, it is put back on the dispatch
list in Q 1. If dropped from Q 1, the virtual machine is placed directly in the Q2 dis
patch list. If the percentage option of the
the deadline priority is calculated at queue drop time by:
current time-of-day + length of allowed processor in-queue time slice
favored percentage
User Priority
For example, if the processor in-queue time slice is 1 second, and the specified per
centage is
onds. The virtual machine should receive one processor time slice (1 second) once
every
Note, however, that these options can impact the response times of other virtual
machines. To provide a virtual machine with both options, basic and percentage,
both forms of the command for that virtual machine must be issued. The percent
age form of the
logged-on virtual machines.
Although the
%
a particular virtual machine, nothing is done to prevent allocating more than 1
favored virtual machines compete for the available resources on a pro-rata basis.
An individual virtual machine's allocation is, roughly, proportional to the percent
age allocated to it, divided by the total percentage allocated to all virtual machines.
The effect of allocating more than
responses is unpredictable.
Note: The percentage of the processor time actually received by the favored
However, it is not an absolute value, and varies depending on the total load on the
system and the type of load on the system. If, for example, there are multiple vir
tual machines on the runlist that are compute bound (That is, are not queue
dropped before the end of their in-queue time slice), then the favored user may not
receive its requested percentage of the total processor time.
The
machines. In so doing, the virtual machine with a higher priority is allocated a larg
er share of the system resources before a virtual machine with a lower priority.
User priorities are set by the following class A command:
where userid is the user's identification and nn is an integer value from 1 to 99.
The value of nn affects the user's dispatching priority in relation to other users in
the system. The priority value (nn) is one of the factors considered in the calcu
lation of the deadline priority. The deadline priority is the basis on which all virtual
machines in the system are ordered on both the eligible list and the dispatch list.
The deadline priority calculation is based on the assumption that the average or
normal (default) user priority is 64.
Performance Guidelines 31