MeasureUp Test Performance Analysis 2

Question 1

Which metric directly measures the percentage of time a CPU is actively executing instructions rather than waiting for I/O?

Accepted Answer

CPU utilization

Answer

CPU utilization measures the fraction of time the processor spends on non-idle work.

Question 2

In a performance baseline, what is the primary purpose of collecting metrics during off-peak hours?

Accepted Answer

To establish a normal low-load reference point

Answer

Off-peak baselines capture minimum expected resource use, enabling comparison when load increases.

Question 3

A web service shows high response times but low CPU utilization. Which bottleneck is most likely responsible?

Accepted Answer

I/O or network contention

Answer

High latency with low CPU points to waiting on disk or network rather than compute saturation.

Question 4

What does a 'p99' latency value represent in performance analysis?

Accepted Answer

The latency that 99% of requests fall below

Answer

p99 (99th percentile) means 99% of requests complete faster than that value, capturing tail latency.

Question 5

Which tool is best suited for profiling CPU hotspots in a running JVM application without restarting it?

Accepted Answer

async-profiler

Answer

async-profiler attaches to a live JVM and samples stack traces to identify CPU hotspots.

MeasureUp Practice Test