MPE/iX Commands Reference Manual (32650-90877)

608 Chapter14
Command List XII
Commands STREAM thru XEQ
NOTE With Release 5.0 of MPE/iX, all three circular scheduling subqueues, CS, DS,
and ES, have dynamically calculated quantums. By default, the DS and ES
subqueues have their bounds set to the same value.
If the values specified for
max are too large, system response may become erratic. If they
are too small, excessive memory management may occur due to frequent process
swapping. Either case degrades system performance. The values for
min and max may
range from 1 to 32,767. The recommended settings are listed in the table below.
The timeslice value determines how long a process in a given scheduling subqueue will be
allowed to hold the CPU. This value is different than the quantum, which determines how
rapidly process priorities decay. The timeslice does interrupt the process if the process is
interruptable. The timeslice is a multiple of 100 milliseconds and has a minimum value of
100 milliseconds.
The following default settings are established when the system is booted from the system
disk (a START RECOVERY or START NORECOVERY), unless the user has customized a TUNE
configuration.
START RECOVERY or START NORECOVERY
CQ base: 152 DQ base: 202 EQ base: 240
limit: 200 limit: 238 limit: 253
min: 1 min: 2000 min: 2000
max: 2000 max: 2000 max: 2000
boost: DECAY boost: DECAY boost: DECAY
tslice: 200 tslice: 200 tslice: 200
NOTE The MPE/iX Scheduler now supports the workgroup concept. However,
backward compatibility is maintained through five default workgroups
created by the system. The scheduling characteristics of the CS_Default,
DS_Default, and ES_Default workgroups mimic those of the CS, DS, and ES
scheduling subqueues. In fact, changing the scheduling characteristics of the
CS, DS, and ES scheduling subqueues, via the TUNE command, is equivalent
to changing the characteristics of the corresponding default workgroup
through ALTWG. Please refer to the NEWWG and ALTWG commands for more
detail.
Workload Manager users should use ALTWG rather than TUNE since TUNE does
not modify user-defined workgroups. If you aren't using Workload Manager,
and you want to change one of the system-defined workgroups, you may wish
to use ALTWG because it only examines member processes of a specific
workgroup and not all processes on the system.
The TUNE command may be issued from a session, job, program or in BREAK. Pressing
Break has no effect on this command. TUNE requires System Supervisor (OP) or System
Manager (SM) capability.