🔬 CPU & Memory Profiling (Flamegraphs)

Identifying performance bottlenecks, CPU hot paths, and unexpected heap memory allocations in production systems requires low-overhead profiling tools.

This guide details generating CPU Flamegraphs and profiling memory allocations in Rust.

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1. Generating Flamegraphs with cargo-flamegraph

Flamegraphs visualize CPU stack traces. The wider a function frame appears on the horizontal axis, the more CPU time it consumed.

Installation

cargo install flamegraph

Running Profiler

Enable debug symbols in release mode inside Cargo.toml:

[profile.release]
debug = true

Run flamegraph generator while applying load with wrk or ab:

cargo flamegraph --bin ferrox-showcase

Output: A vector SVG graph flamegraph.svg highlighting exact CPU hot spots down to line numbers.

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2. Heap Profiling with heaptrack or valgrind

To detect memory leaks or excessive buffer allocations:

heaptrack ./target/release/ferrox-showcase

Launch heaptrack GUI to inspect allocations:

heaptrack_gui heaptrack.ferrox-showcase.12345.gz