Performance Fundamentals and Troubleshooting Questions

Core skills for identifying, diagnosing, and resolving general performance problems across applications and systems. Topics include establishing baselines and metrics, using monitoring and profiling tools to determine whether issues are CPU bound, memory bound, input output bound, or network bound, and applying systematic troubleshooting workflows. Candidates should be able to prioritize fixes, recommend temporary mitigations and long term solutions, and explain when to escalate to specialists. This canonical topic covers general performance awareness, common diagnostic tools, and basic remediation approaches for slow systems and resource exhaustion.

HardSystem Design

100 practiced

Design a synthetic testing strategy to detect tail-latency regressions before they reach customers. Include test harness architecture, traffic patterns to emulate, how to seed rare code paths, and what thresholds should fail the build or block a rollout.

HardTechnical

65 practiced

A distributed service shows sporadic 5-10 second latency spikes. Metrics show brief CPU usage increases and GC pause time increases at the same times, but also an uptick in external API retries. Propose a root cause analysis plan that accounts for these mixed signals and outline how you'd isolate the true cause.

EasyTechnical

51 practiced

Explain, in plain terms, what a 'garbage collection pause' is and how it can affect latency for a Java or Go backend. Include one immediate mitigation and one long-term remediation strategy.

EasyTechnical

52 practiced

Explain the difference between CPU-bound and IO-bound processes. Give a concise example of a real backend workload for each and describe one immediate mitigation you would apply if you observed a production service exhibiting that behavior.

EasyTechnical

67 practiced

Create a short runbook (bullet steps) for an SRE to follow when a service's p95 latency doubles after a deployment. The runbook should include immediate actions to reduce user impact, diagnostic steps, and criteria for rollback.

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