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myunusov / pm

Performance Model Calculator
http://myunusov.github.io/pm/components/
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Interactive Response Time Law #22

Closed myunusov closed 9 years ago

myunusov commented 10 years ago

Example 3.8.

A client/server system is monitored for one hour. During this time, the utilization of a certain disk is measured to be 50%. Each request makes an average of two accesses to this disk, which has an average service time equal to 25 msec. Considering that there are 150 clients and that the average think time is 10 sec, what is the average response time?

The known quantities are: Udisk = 0.5, Vdisk = 2, Sdisk = 0.025 sec, M = 150, and Z = 10 sec. From the Utilization Law,

Thus, Xdisk = 0.5/0.025 = 20 requests/sec. From the Forced Flow Law,

Finally, from the Interactive Response Time Law, R = 5 sec.

This case is incorrect in PM calc

myunusov commented 10 years ago

image

myunusov commented 10 years ago

In the case of open models, the throughput is equal to the arrival rate