Keep utilization below 70%. Above 80%, p99 latency explodes non-linearly. The "knee" is your capacity limit in practice.
Latency vs Throughput in ML Serving - Interactive Visualization
Latency and throughput have a non-linear relationship in ML serving systems. As throughput approaches capacity, latency increases exponentially - this is the M/M/1 queue behavior. The 'knee of the curve' is around 70% utilization: above that, p99 latency explodes. Little's Law (L = λW) governs queue depth. Adding replicas shifts the saturation point right but does not change the shape of the curve. Caching reduces effective load on the model serving layer.
Little's Law: queue length L = arrival rate λ × wait time W - all three scale together
The knee of the curve is at ~70% utilization - design for peak below this threshold
p99 latency is 3–5× p50 at moderate load, and 10–50× at high utilization
Adding replicas scales capacity linearly - the safest way to reduce p99 without code changes
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