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Cloud Providers: Computing service providers whose product/platform is based on virtualization of computing resources and a utility-based payment model.
Transaction analysis: • For each transaction under test you should: – State and document each execution step and hence the
Define testing scenarios: • Contractually obligated usage scenario(s) • Usage scenarios implied or mandated by performance-testing aim
Performance Testing tools:• Scripting module:– Enables recording of end-user activity and may support many different middleware protocols. Permits modification of the recorded scripts to as
Performance management process:1. Identify key scenarios. Identify scenarios where performance is important and scenarios that pose the most risk to your performance objectives. Quantify requirements2
Performance analysis & testing: What distinguishes engineers from technicians is largely the ability to formulate and carry out the detailed calculations of forces and deflections, concentrations
Draw a queuing diagram for the systems below and describe them using Kendall’s notation: A) Single CPU system B) 4&nb
Software monitor data for an interactive system shows a CPU utilization of 75%, a 3 second CPU service demand, a response time of 15 seconds, and 10 active users. Determine the average think time of t
A grocery store chain is considering ways to improve the performance of the waiting lines at their checkout stands. A heavily trafficked checkout stand is monitored for 120 min. In that period, 60 cus
Part (a). Draw a state diagram for a car with the following state variables: D indicating whether the car is in drive; B indicating the brake pedal is depressed; G indicating the gas pedal is depresse
SPIN: • SPIN generates C program that is the model checker – The pan verifier • Process Analyzer – Run the pan executable to do the model checking • SPIN simulation modes
Building Models • What do we need to know to build a model?– For model checking we need to specify behavior • Consider a simple vending machine – A custome rinserts coins, sele
Safety and Liveness in Model Checking Approach; •? Safety: Nothing bad happens •? Liveness: Something good happens •? Model checking is especially good at verifying safety and livene
Model Checking Approach: • Specify program model and exhaustively evaluate that model against a speci?cation –Check that properties hold &nb
Networks of queues • Typically, the flow of customers/request through a system may involve a number of different processing nodes.– IP packets through a computer network– O
Service times:A) In most cases, servicing a request takes a “short” time, but in a few occasions requests take much longer.B) The probability of completing a service request by time t, is
Inter-arrival times:A) Requests arrive randomly, often separated by small time intervals with few long separations among themB) The time until the next arrival is independent of when the last arrival
Interactive Response Time Law: • R = (L/X) - Z• Applies to closed systems.• Z is the think time. The time elapsed since
Utilization Law: • ρk = XK . SK = X . DK • Utilization of a resource is the fraction of time that resource is busy proc
Service Demand Law:• Dk = SKVK, Average time spent by a typical request obtaining service from resource k• DK = (ρk/XK) (
Forced Flow Law: • The forced flow law captures the relationship between the various components in the system. It states that the throughputs or flows, in all parts of a system must be
Simplified demonstration of Little’s Law: • a(t): the number of arrivals up to time t• d(t): the number of depa
Little’s Law: • L = λR = XR • Lq = λW = XW • Steady state system • Little’s Law holds as long as customer
Derived quantities in Queuing system: • λ = A / T, Arrival rate • X = C / T, Throughput or completion rate • &