Pathwise

Manuals / Performance Testing Basics / Chapter 6

B · Execute · intermediate · ~35 min · Chapter 6 of 9

Reading graphs honestly

Correlate latency, errors, and system metrics. Averages hide pain. Coordinate drops. Watch for coordinated omission and client-side bottlenecks.

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Read a run

When p95 climbs, do errors climb? Is CPU maxed? DB locks?

Read a runDrag stickies · tap for tips
Study mapDrag stickies · tap for tipsKeep it shortdrag · tap →Name the waitdrag · tap →Scope locatorsdrag · tap →Trace when stuckdrag · tap →One browser firstdrag · tap →Isolate statedrag · tap →Assert the UIdrag · tap →Retry wiselydrag · tap →Seed datadrag · tap →Close the loopdrag · tap →Keep it shortdrag · tap →Name the waitdrag · tap →Scope locatorsdrag · tap →Trace when stuckdrag · tap →One browser firstdrag · tap →Isolate statedrag · tap →Pathwise hackdrag · tap →Read a rundrag · tap →Try thisdrag · tap →Follow the dashed drag · tap →

Do this now

Annotate one test run: hypothesis for the bottleneck in 3 bullets.

Pro tip: If the load generator is saturated, you’re measuring your laptop.

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Chapter learning outcomes
  • Percentile graphs
  • Error correlation
  • Bottleneck hypotheses

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