Intel 7xx Servers, 170 Servers, AS/400 RISC Server manual Vios

The following charts are a view of the characteristics we observed during our Commercial Performance Workload testing on our JS22 Express. The first chart shows the effect on the Commercial Performance Workload when we apply 3 Dedicated processors and then switch to 3 shared processors. Then incremented the number of virtual processors available.

The “red line” is our dedicated processor set up, which is our baseline. The “blue line” is turning on shared processors in what I might have thought of as a fair comparison where 1 virtual processor was assigned for each real processor, resulting in 1 virtual processor for VIOS and 3 virtual processors for IBM i operating system. The Next experiment the “green line” was to increase the number of virtual processors assigned to VIOS but not the number of virtual processors assigned to IBM i operating system. Four virtual processors assigned to VIOS seemed to worked best for our environment. Next was to increase the number of virtual processors assigned to the IBM i operating system environment. Six virtual processors seen in the “purple line” optimized our environment best. As I increased from 6 virtual processors I started losing performance until I had increased to the 28 virtual processors available to me shown in the “dark red line”

Not all workloads will react in the same way but it is important to note that a small change to your configuration can have a large influence on your performance positive and negative. .

				IBM i operating system JS22 Express
				Commercial Performance Workload
	10
	1
(sec)
Response Time	0.1
	0.01
	0.001
	20000	25000	30000	35000	40000	45000	50000	55000	60000
					Transactions/Minute
	DS4800 3 Dedicated Processors IBM i operating system, 1 Shared Porcessor 4 Virtual Processors VIOS
	DS4800 3 Shared Processors 3 Virtual Processors IBM i operating system, 1 Processor 1 Virtual Processors VIOS
	DS4800 3 Shared Processors 3 Virtual Processors IBM i operating system, 1 Shared Processor 4 Virtual Processor VIOS
	DS4800 3 Shared Processors 6 Virtual Processors IBM i operating system, 1 Shared Processor 4 Virtual Processors VIOS
	DS4800 3 Shared Processors 28 Virtual Processors IBM i operating system, 1 Shared Processor 4 Virtual Porcessors
	VIOS
IBM i 6.1 Performance Capabilities Reference - January/April/October 2008

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