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2948 questions of the kind that actually get asked — in interviews, in architecture review boards, and by the person who has to run the thing at 3 AM. Every answer states the trade-off rather than the slogan, and says when the obvious choice is the wrong one.

All areas2948 Architecture Fundamentals91 Distributed Systems101 Data Architecture90 Cloud Architecture87 Networking96 API & Integration Architecture87 Reliability & Resilience99 Observability92 Performance & Capacity Engineering100 Security Architecture105 Cost Architecture & FinOps102 Business Architecture103 Architecture Communication102 Enterprise Architecture100 Legacy Modernization102 AI-Era Architecture106 Software Architecture & Engineering93 Architecture Patterns94 Architecture Decision-Making101 The Architect's Meta-Skills102 Delivery & Release Engineering103 Platform Engineering & Developer Experience102 Testing & Quality Architecture102 Data Platform Architecture98 Streaming & Real-Time Data103 Data Governance & Semantics91 Frontend & Experience Architecture101 Edge, Mobile & IoT98 Regulatory & Data Protection Architecture99 Assurance, Audit & Model Risk98
Difficulty Any beginner intermediate advanced

4 questions in Profiling & Optimisation.

  1. Profiling & Optimisation intermediate Multiple choice

    A colleague spent a week optimising a function and the endpoint is 2% faster. What went wrong in the approach?

    2 min answer optimisationamdahlprofilingmethod
  2. Profiling & Optimisation intermediate Multiple choice

    A service's p99 is 300 ms and an hour-long sampling CPU profile shows no single function above 4% of samples. The flame graph is wide and shallow everywhere. What does that tell you to do next?

    3 min answer profilingflame-graphoff-cpuamdahl
  3. Profiling & Optimisation intermediate

    A team has profiled a service and found the top three functions by CPU time. Why is optimising them often the wrong next step?

    2 min answer profilingoptimisationamdahlmeasurement
  4. Profiling & Optimisation advanced

    Discord's Read States service, written in Go, showed latency spikes every two minutes like clockwork. The team had written it carefully with very few allocations, and the spikes appeared regardless of load. Their published account from 2020 explains the cause and the rewrite that followed. What was happening, and what does it teach about periodic latency?

    3 min answer discordgarbage collectiontail latencyruntime