Network Router User Manual

GINA V4.0 System Administrator Guide – September 2000 49

Configuration language

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RELATIVE attribute: Relative priority

Free processes will be assigned to higher priority classes more often than lower priority

classes provided that there are pending or interrupted requests for these higher priority

classes. If there are requests present for all classes, a free process will be assigned to

TAC class 9 twice as often as to TAC class 10, and twice as often to TAC class 10 as to

TAC class 11, etc.

EQUAL attribute: Equal priority

All classes will be serviced equally if there are requests present. This equal distribution

can be disrupted if a class does not contain any pending requests at times or subpro-

gram runs with blocking calls (e.g. KDCS call PGWT) frequently occur in that class.

Further information on the RELATIVE, ABSOLUTE and EQUAL attributes can be found in

the

open

UTM documentation V5.0A, Generating and Handling Applications [26] in the

section entitled TAC-PRIORITIES – specify priorities of the TAC classes.

The following TIMER, EVENT, CONTROL and PGWT attributes are optional and can be spec-

iﬁed in any order.

TIMER attribute

The T-ORB runtime system has an internal cyclical timer. This is a cyclical order (con-

trolled by means of the CYCLETIME statement of the config generator) that takes

over various tasks within T-ORB, e. g. initiation of the EventControl mechanism (see the

EVENT attribute).

The TIMER attribute can be used to determine which priority class is to be assigned to

the internal cyclical timer. TIMER can only be speciﬁed for one priority class. If the TI-

MER attribute is not speciﬁed, the class with the average priority (rounded up to the next

highest priority) will be assigned to the cyclical timer. If, for example, PRIO1 through

PRIO4 is speciﬁed, PRIO2 will be assigned to the timer.

EVENT attribute

The T-ORB runtime system maintains the so-called EventControl mechanism internally.

This mechanism is responsible for ensuring that requests to T-ORB/client applications

that are buffered in the T-ORB application for technical reasons are actually delivered.

The EVENT attribute can be used to determine the priority class in which the

EventControl mechanism is to run. EVENT can only be speciﬁed for one priority class.

If the EVENT attribute is not speciﬁed, the class with the average priority (rounded down

to the next lowest priority) will be assigned to the EventControl mechanism. If, for ex-

ample, PRIO3 through PRIO7 is speciﬁed, PRIO5 will be assigned to the EventControl

mechanism.

This attribute is only needed if T-ORB/client applications are connected to the T-ORB

application.