Comparisons
Two tools, two questions. Neither column wins — what decides is which question you actually have in front of you.
Metrics vs TracesTracing vs ProfilingUtilization vs Saturationp50 (median) vs p99 (tail)Add capacity vs Fix the bottleneckLoad test vs Production telemetryCause-based alerts vs Symptom-based alertsMicrobenchmark vs End-to-end benchmark
Microbenchmark vs End-to-end benchmark
A microbenchmark measures one operation precisely; an end-to-end benchmark measures the system approximately. The classic error is optimizing a function by 40% in isolation and moving p99 by nothing.
MicrobenchmarkOpen lesson →
Best for
Comparing two implementations of the same operation
Blind to
Whether the operation matters to the system at all
Costs
Cheap to run, easy to fool yourself with
Answers
"Is this function faster?"
End-to-end benchmarkOpen lesson →
Best for
Deciding whether a change is worth shipping
Blind to
Which component is responsible for the number it produces
Costs
Expensive to build and keep representative
Answers
"Did the product get faster?"
| Dimension | Microbenchmark | End-to-end benchmark |
|---|---|---|
| Scope | One function, warm and isolated | The whole request path |
| Classic trap | The compiler optimized the work away | The bottleneck was somewhere you did not vary |
| Use for | Choosing between implementations | Deciding whether to ship |