Intel AS/400 RISC Server, 170 Servers, 7xx Servers manual Affects of Server Dynamic Tuning

Server Dynamic Tuning Recommendations

On the new systems and mixed mode servers have the QDYNPTYSCD and QDYNPTYADJ system value set on. This preserves non-interactive capacities and the interactive response times will be dynamic beyond the knee regardless of the setting. Also set non-interactive class run priorities to less than 35.

On earlier servers and 2/98 model 170 systems use your interactive requirements to determine the settings. For “pure interactive” environments turn the QDYNPTYADJ system value off. in mixed environments with important non-interactive work, leave the values on and change the run priority of important non-interactive work to be less than 35.

Affects of Server Dynamic Tuning

Server Dynamic Tuning - .	Server Dynamic Tuning
High "Server" Demand	Mixed "Server" Demand

	100					100
CPU	80				CPU	80
	60	Available for				60	Available for		available
				available					O.H. or Server
Available		Client/Server			Available		Client/Server
	40			interactive		40			Int. or Server
		Knee					Knee		interactive
	20					20
	0					0
	0	1/3 Int-CPW	Full Int-CPW			0	1/3 Int-CPW	Full Int-CPW

Fraction of Interactive CPW Fraction of Interactive CPW

With sufficient batch or client/server load, Interactive is constrained to the "knee-level" by priority degradation

Interactive suffers poor response times

Without high "server" demand, Interactive allowed to grow to limit

Overhead introduced just as when Dynamic Priority Adjust is turned off

Figure 2.6.

IBM i 6.1 Performance Capabilities Reference - January/April/October 2008
© Copyright IBM Corp. 2008	Chapter 2 - Server Performance Behavior	28