Performance Budgets
Targets enforced in CI so regressions fail the build.
4 to work through
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intermediate
A design platform's web application has grown steadily slower with no single change responsible. What mechanism prevents this, and how should it be enforced?
2 min answer -
intermediate
A web experience for low-end devices on slow networks keeps regressing despite good intentions. What mechanism prevents this, and what must it measure?
2 min answer -
intermediate
What does a latency budget give you that a latency target does not?
2 min answer -
intermediate
What is a performance budget, why do most attempts at one fail, and how should it be enforced so it actually constrains behaviour?
2 min answer
2 terms in this topic
Performance Budget
A stated numeric limit on a performance characteristic, enforced automatically so that regressions fail a build rather than accumulating.
practicePerformance Budget for Backends
A latency or resource allowance allocated per component of a request path, so that the end-to-end target is composed rather than hoped for.
Neighbouring topics
Performance & Capacity
General material on performance and capacity engineering.
Latency
Distributions rather than averages, and the floors physics imposes.
Throughput
Work completed per unit time, and why it trades against latency.
Concurrency
Operations in flight, and the limits that are the real capacity ceiling.
Queueing Theory
Why latency explodes as utilisation approaches capacity.
Little's Law
L = λW, and the pool sizes it computes directly.
Bottleneck Analysis
Finding the constraint, and expecting a second one behind it.
Tail Latency
p99 behaviour, amplification across fan-out, and hedged requests.
Load Testing
Realistic data, realistic mix, and a ramp rather than a step.
Stress Testing
Pushing past target to learn what breaks first and how it fails.
Soak Testing
Long runs that surface leaks and slow degradation.
Capacity Modelling
Arithmetic before load tests, and headroom for failure as well as peak.
Horizontal vs Vertical Scaling
Scale out for stateless, scale up first for stateful.
Caching for Performance
Layer choice, hit ratio as a first-class metric, and cold-cache recovery.
Database Performance
Plans, indexes, contention and the pool in front of the database.
Connection Pooling
The most common hidden ceiling, and the metric nobody collects.
Network Performance Tuning
Keep-alive, compression, payload size and round-trip elimination.
Profiling & Optimisation
Measuring before optimising, and optimising the dominant term.
Peak Event Readiness
Freeze, pre-scale, shed order, warm caches and rehearse.