Generated from C.60.01 /SYS/PUB/CICAT last modified on Thu Jan 11 09:18:52 2001
Changes the scheduling characteristics of the scheduling queues. These characteristics include base and limit priorities, quantum bounds (min and max), boost property and timeslice. (NM)
{CQ} TUNE[minclockcycle][[;]{DQ}=[base],[[limit][,[min][,[max] {EQ} [,[{decay }]][,[tslice]]]]] {oscillate} [[;]...]
Misuse of this command can significantly degrade system operating efficiency.
minclockcycle THIS PARAMETER IS IGNORED. IT APPEARS HERE FOR MPE V/E COMPATIBILITY ONLY. base An integer from 150 to 255 specifying the priority at which user processes executing in the CS, DS, and ES scheduling queues begin their Dispatcher transactions. Priority is inversely related to the integer: a higher-priority process has a lower number. While the full range is provided for compatibility, avoid setting the base priority between 150 and 152, since user processes running at priorities greater than 152 can adversely affect system performance. limit An integer specifying the lowest priority at which a process in the CS, DS, or ES scheduling queues can execute. Priority is inversely related to the integer: a higher-priority process has a lower number. The limit, which can range from 150 to 255, must be greater than or equal to the base. min The minimum quantum is a lower bound for the dynamically calculated quantum (average transaction time) value. The quantum value determines the rate of priority decay for processes within the scheduling queue. Values range between 1 and 32767 milliseconds. max The maximum quantum is an upper bound for the dynamically calculated quantum (average trans- action time) value. The quantum value determines the rate of priority decay for processes within the scheduling queue. Values range between 1 and 32767 milliseconds. The value of max must be greater than or equal to the value of min. DECAY Indicates if the queue is to demonstrate the default decay behavior associated with circular queues If set, a process decays normally to the limit of the queue and returns to the base when the transaction is completed. DECAY is the default. OSCILLATE Indicates if the queue is to demonstrate oscillation. If set, a process is placed back to the base of the queue once its priority has decayed to the limit of the queue, even if it has not completed a dispatcher transaction. tslice The number of milliseconds a process in a given queue can keep the CPU once it gets the CPU. A process holding the CPU for this number of milliseconds will be timesliced. This value is accurate to the nearest 100 milliseconds and has a minimum value of 100 milliseconds.
The system manager uses the TUNE command to change the characteristics of the circular scheduling queues to more efficiently manage the current processing load. This command may be issued from a session, job, or in BREAK, but not from a program. Pressing [Break] aborts the execution of this command. It requires system supervisor (OP) or System Manager (SM) capability. Processes in the CS, DS, and ES scheduling subqueues typically begin execution at the base priority. When a process stops (for disk I/O, terminal I/O, preemption, etc.), the amount of CPU it has consumed is used to determine its new priority. If the process has completed a Dispatcher transaction, typically by issuing a terminal read, its priority is reset to the base, and the quantum value for that workgroup is recalculated. If the process has exceeded the quantum (filter) value since its priority was last reduced, the priority is decreased without exceeding the limit priority. If the boost property for the workgroup is oscillate, process priorities are reset to the base value once they decay to the limit. Min and max refer to the absolute bounds of the quantum ("system average quantum", or SAQ) or a filter representing the average transaction time of processes in the queue. For the CS, DS, and ES scheduling queues, the quantum is recomputed after every user Dispatcher transaction is complete and then compared against the CPU time of the process to determine whether the priority of the process should be decreased. If the values specified for max are too large, system response may become erratic. If they are too small, excessive memory management may occur as a result of frequent process swapping. In either case, system performance is degraded. The values for min and max may range from 1 to 32,767. The recommended settings are listed below in the table of default values for START RECOVER or START NORECOVER. A user Dispatcher transaction completes under several circumstances, including the following: o waiting for a terminal read o waiting for a parent or child wait o waiting for an IPC message file o waiting for the PAUSE intrinsic if pause time exceeds one second Parameters are positional. For example, to change min without specifying base and limit, precede it with commas. The following default settings are established when the system is coldloaded from the system disk (a START RECOVER or START NORECOVER). The values assigned for limit specify the lowest priority (largest number) that the system can assign to a process in a particular queue. START RECOVER or START NORECOVER 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
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 queues. In fact, changing the scheduling characteristics of the CS, DS, or ES queue via the TUNE command is equivalent to changing the characteristics of the corresponding default workgroup through ALTWG. Workload Manager users should use ALTWG rather than TUNE since TUNE does not modify user-defined workgroups. If you aren't using the 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. To change more than one system-defined workgroup, TUNE, which allows you to specify the CQ, DQ and EQ in a single command, is more efficient.
To set CQ base to 152, limit to 200, and CQ maximum filter to 300; and DQ base to 202, DQ limit to 238, DQ (and EQ) minimum and maximum filter to 1000, and cause oscillation boosting enter: TUNE CQ=152,200,300,300;DQ=202,238,1000,1000,OSCILLATE To set the CS queue to oscillation with a 300 millisecond timeslice and the DS queue's base to 180, limit to 238, boost property to decay, and timeslice to 1500, enter: TUNE=CQ=,,,,OSCILLATE,300;DQ=180,238,,,DECAY,1500
Commands: SHOWQ, ALTPROC, SHOWPROC, NEWWG, ALTWG, PURGEWG, SHOWWG Manuals : Process Management Programmer's Guide (32650-60011) Back to Main Index