Performance Benchmarking & Tuning Flashcards
7 cards from real CSI practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Performance Benchmarking & Tuning flashcards as text
What does the acronym 'IOPS' measure in storage performance benchmarking?
Answer: Input/Output operations per second
IOPS measures how many read or write operations a storage device can perform per second, a key metric for evaluating storage performance.
During a stress test, which condition signals that a system has reached its 'breaking point'?
Answer: Error rate rises sharply and throughput drops simultaneously
The breaking point is characterized by both a spike in errors and a drop in throughput, indicating the system can no longer handle additional load.
Which HTTP keep-alive setting tuning reduces connection overhead in a high-request-rate web application?
Answer: Increasing the keep-alive timeout and maximum requests per connection
Increasing keep-alive timeout and max requests per connection allows more requests to reuse established TCP connections, reducing handshake overhead.
A system integrator notices that adding more threads beyond a certain count actually decreases throughput. Which principle explains this?
Answer: Amdahl's Law and thread contention overhead
Amdahl's Law predicts diminishing returns from parallelism, and excessive threads introduce contention overhead that outweighs the parallelism benefit.
What is the main advantage of using percentile-based SLAs (e.g., p99) over average-based SLAs for latency targets?
Answer: Percentiles capture tail latency experienced by the worst-affected users
Average latency can mask severe slowdowns for a subset of users, while percentile-based SLAs ensure that even the worst-case users receive acceptable service.
In network performance tuning, increasing the TCP receive window size primarily improves:
Answer: Throughput on high-latency, high-bandwidth links
A larger TCP receive window allows more data to be in flight before an acknowledgment is required, which maximizes throughput on high-latency links.
Which of the following best describes 'think time' in a load testing scenario?
Answer: Simulated delay between user actions to mimic real user behavior
Think time is an intentional pause inserted between virtual user actions to simulate the time a real user spends reading or processing a page before acting again.