Load Testing · Senior · Question 4 of 76
A page calls 100 backend services in parallel, each with p99 = 1 s. Roughly what share of page loads see at least one 1 s+ call?
- 1About 10%
- 2About 1%
- 3About 63%
Show the answer
Correct answer: About 63%
Explanation
1 − 0.99^100 ≈ 0.63. Fan-out turns a rare tail into a common one, which is why tail latency matters so much in large systems.