SCHDOPT parameter

Scheduler options

Summary

Default value

0

Parameter type

System

Where set

On User 0's parameter line or reset by system manager.

Related products

All

Introduced

Model 204 V6.1 or earlier

Description

Control of the main task scheduler operation and accounting.

• Setting X'10' is relevant to all sites.
• All other settings are relevant only to sites running MP/204.

Valid settings of SCHDOPT, which can be summed, are as follows:

Setting	Meaning
X'00'	No scheduler overhead tracking, no forced offload. This is the default.
X'01'	Maintain MAINTASK scheduler overhead.
X'02'	Run MP work on an MP subtask even if MAINTASK is not busy.
X'04'	Defer page releases until server swap.
X'08'	Do server I/O on MP subtask.
X'10'	In CSLICE, check maximum values even if there is an SWAIT.
X'20'	Run zIIP work on a zIIP subtask even if MAINTASK is not busy.
X'40'	Run zIIP work on a zIIP subtask even if MP subtasks are not busy.
X'80'	Allow server swapping to be offloaded to zIIP processors. If you have SCHDOPT=80 set, then you probably want to set SCHDOPT1=01 as described in the "Usage Notes" below. The X'80' setting is only valid when CCASERVR is in memory (servers swapped into memory). If you set SCHDOPT=X'80' when CCASERVR is not in memory, the setting X'80' is reset and message 2914 is issued: SCHDOPT INDICATION OF SERVER SWAPPING DONE BY ZIIP IS ONLY VALID WHEN CCASERVR IS IN MEMORY Initialization then continues.