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Lund Performance Solutions


Altering Process Priorities-"Q-Jumping"
The SOS/3000 Q-Jump feature allows a user with OP or SM capability to alter the priority and/or scheduling queue of a live, running process. This is often helpful as a tactical mechanism to either favor or penalize certain processes. The MPE TUNE command is helpful from a strategic and global standpoint. Often there is a single renegade process that can be sent to the E subqueue to free the CPU for other processes.

Using the Q-Jump Feature

In order to change the priority or queue of a process go to UTILITY KEYS (F6) and select F3 - QUEUE JUMP. The following will appear:
Enter Process Identification Number of process to reschedule:
You must then select the PIN number of the process whose priority you want to alter. After entering the desired PIN the following statement will appear:
Process ppp current priority is X
or
Process ppp current priority is Lnnn

ppp
The PIN number.
X
A letter representing the current scheduling queue in which the process is running (A, B, C, D, or E).
L
A linear priority has been assigned
nnn
The current absolute of the process (0-225) if an absolute priority has been selected.

The following question will appear:
What should its new priority be?
The new queue priority can be entered in the general form “qcddd”, where:

q
is the priority queue (B, C, D, or E) which defaults to B if not entered. SM capability is required to place processes in the B queue or to alter the priority of a process which is in the B queue.
c
is an optional qualifier which specifies the process behavior within the queue (L for linear and S for circular). If “c” is not qualified, the defaults are L for the B queue and S for C, D, and E queues. A circular (S) queue priority will be adjusted by the MPE queue dispatcher according to how you have tuned your system (i.e., OSCILLATE or DECAY). A linear (L) queue priority will keep a process at a fixed priority. “S” may not be specified for the B queue.
ddd
is an optional number MPE priority. It can only be specified for linear (L) queues. It must be within the scheduling queue’s base and limit priority as defined by the TUNE command, or in the range 100-150 for the BL queue. If not entered, 150 is the default for the B queue. The default for the other scheduling queues (C, D, and E) is their base priority.

Examples


B130
B linear queue, priority 130
D or DS
D circular queue
CL152
C linear queue, priority 152

After you have selected either a queue letter or linear priority the following confirmation will be shown:
Confirm process ppp priority change from Xnnn to Ymmm (N)?
If you want to execute the priority change, answer Y (Yes) otherwise press N (No) or hit C/R for the default N. If you reply Y then SOS/3000 will let you know that the priority was successfully changed.

Lund Performance Solutions
www.lund.com
Voice: (541) 812-7600
Fax: (541) 812-7611
info@lund.com
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