CSI Performance Benchmarking & Tuning 2

Question 1

Which metric best indicates whether a system is CPU-bound versus I/O-bound during a benchmark run?

Accepted Answer

CPU utilization vs. I/O wait percentage

Answer

Comparing CPU utilization to I/O wait time reveals whether the bottleneck is processing power or storage throughput.

Question 2

A load test shows response times increase linearly with user count up to 100 users, then spike sharply. What does this pattern most likely indicate?

Accepted Answer

A resource saturation point has been reached

Answer

A sudden spike after linear scaling indicates a saturation point where a bottlenecked resource can no longer queue additional requests efficiently.

Question 3

What is the primary purpose of a 'warm-up' phase at the start of a performance benchmark?

Accepted Answer

Allow JIT compilation and caches to reach steady state

Answer

A warm-up phase lets the JVM JIT-compile hot paths and populate caches so benchmark measurements reflect steady-state performance rather than cold-start overhead.

Question 4

In capacity planning, the term 'headroom' refers to:

Accepted Answer

The unused resource capacity reserved for traffic spikes

Answer

Headroom is the intentional buffer of unused capacity kept available so unexpected load spikes do not immediately saturate the system.

Question 5

Which profiling technique adds the least overhead and is most suitable for production environments?

Accepted Answer

Sampling profiler

Answer

Sampling profilers interrupt execution at intervals to record the call stack, adding minimal overhead compared to instrumenting every method call.

(CSI) Certified System Integrator Practice Test

(CSI) Certified System Integrator Practice Test

CSI Performance Benchmarking & Tuning 2