Pathwise

Manuals / Performance Testing Basics / Chapter 2

A · Define good · beginner · Week 1 · Chapter 2 of 9

SLIs, SLOs & user perception

SLI = what you measure. SLO = target. Latency percentiles (p95/p99) beat averages. Errors and saturation complete the picture.

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Step 1 of 1

Define SLIs

For your journey: success rate, latency p95, maybe throughput.

  • Latency — p50/p95/p99
  • Errors — 5xx / business failures
  • Saturation — CPU, pool, queue depth
Define SLIsDrag 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 →Define SLIsdrag · tap →Try thisdrag · tap →Follow the dashed drag · tap →

Do this now

Write SLIs + draft SLO (e.g. p95 < 500ms at X RPS). Note confidence.

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Chapter learning outcomes
  • Latency percentiles
  • Availability
  • Apdex lite

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