How do you find a CPU hotspot in a .NET service?
PICTURE THIS: DJANGO MVT
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Simple meaning
I start with traces and a profiler, not guesses.
WHY — Performance instead of guessing?
Why interviewers care about Performance:
This is a process
question about Performance.
Panels listen for order,
trade-offs, and what you would actually do on a .NET project - not buzzwords.
Stay structured
Name the idea, why it exists, then one short example.
Close cleanly
End with when you use it and one common pitfall.
STEPS — What happens step by step?
Before you speak the answer, walk the interviewer through these steps:
- 1I start with traces
and a profiler, not guesses.
- 2Allocations show up as
GC time
- 3How it works
hot methods show in sampling.
- 4BenchmarkDotNet is for microbenchmarks
after I know which method matters.
- 5Common mistake
What juniors usually get wrong.
- 6Close
When you pick this over the alternative.
EXAMPLE — See it in action
Here's a short line you can speak, broken into clear beats:
Say this line
“Allocations show up as GC time”
Break into beats
AllocationsshowupasGCtime
Speaking order
2987408337471632900
Note: Adapt this scaffold to your own project — keep it under 60–90 seconds.
Key takeaway
I start with traces and a profiler, not guesses. Allocations show up as GC time