pprof-prof #

Practice scenarios for Go's net/http/pprof endpoints. Each tutorial is a realistic mini-service with a real bug, running under its own load, waiting to be diagnosed with the profiler.

Authoritative spec: backlog/1-pprof-prof/spec.md.

Curriculum #

Dir	Endpoint under study	Symptom
00-setup	all (guided tour)	none
01-goroutines	/debug/pprof/goroutine	goroutine count climbs
02-heap	/debug/pprof/heap	memory footprint climbs
03-cpu	/debug/pprof/profile	a core stays pegged
04-allocs	/debug/pprof/allocs	latency, healthy live heap
05-mutex	/debug/pprof/mutex	requests serialize
06-block	/debug/pprof/block	throughput far below capacity
07-threadcreate	/debug/pprof/threadcreate	OS threads far above the workload
08-trace	/debug/pprof/trace	status pings spike though the API does nothing
99-capstone	none (final exam)	everything at once

Working through an exercise #

1. Read the scenario's README.md: the symptom, the run instructions, and the endpoint to practice.
2. Run the service with go run ./NN-name and let it work for a minute.
3. Diagnose. Fetch profiles, read them with go tool pprof, and point at the guilty code before you open SOLUTION.md.
4. Compare with SOLUTION.md: the diagnosis path, real command transcripts, and the fix as a diff.

Each scenario serves its app on localhost:8080 and /debug/pprof on localhost:6060. Run one scenario at a time.

Environment #

Enter the dev shell for a known-good toolchain:

$ nix develop

The shell carries a C compiler, because go tool pprof is built with cgo and fails on hosts without one. It also carries graphviz, for pprof's graph views.

Outside the shell, if go tool pprof dies with cgo: C compiler "gcc" not found, prefix the command with CGO_ENABLED=0.