A JSON serialization endpoint exhibited p99 latency of 2 seconds, while p50 was 50ms. Diagnosis (via 6.1060 methodology):
[ S = \frac{1}{(1 - P) + \frac{P}{N}} ] Even if 95% of your program is parallelizable (P=0.95), running on infinite cores (N=∞) limits speedup to ( 1 / (1-0.95) = 20x ). The remaining 5% sequential code is the bottleneck. 6.1060 software performance engineering