felixge/fgprof

Health v2 · maintenance only

Adoption not part of the score

3110 stars · 100 forks observed · 2026-08-28

What it is AI-extracted, prompt v1, taxonomy v1, 2026-08-30, confidence not recorded

fgprof is a sampling Go profiler that analyzes both On-CPU and Off-CPU (e.g. I/O) time together, also known as wall-clock profiling. It exposes an HTTP handler compatible with `go tool pprof` and Brendan Gregg's FlameGraph tooling.

Use cases

• profile a Go application with mixed CPU and I/O workloads
• analyze off-CPU time spent waiting on I/O in Go
• generate flame graphs from a running Go service
• complement the builtin pprof CPU profiler with wall-clock profiling
• find where goroutines spend time blocked or sleeping
• profile a Go HTTP server via an HTTP endpoint

When to choose

• your Go application has mixed I/O and CPU workloads
• you need wall-clock profiling that includes Off-CPU time
• you want pprof-compatible output from an HTTP endpoint
• you want to generate flame graphs with Brendan Gregg's tooling

When to avoid

• you only need precise On-CPU profiling - Go's builtin pprof CPU profiler is better at that
• you run Go older than 1.19 with many goroutines, where fgprof can cause significant STW latencies
• you need tracing-level detail of I/O operations rather than sampling

Facets

library · maturity stable

monitoring benchmarking developer-tools performance developer-tools backend go windows cross-platform profiling go-profiler wall-clock-profiling off-cpu-analysis pprof flamegraph sampling-profiler linux macos

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