Profiling modes

hotpath supports two complementary approaches to performance monitoring.

Static reports

Best for CLI tools, tests, or short-lived applications. On exit, hotpath prints a summary of execution time, memory usage, and timing percentiles. Reports can be rendered as readable tables or exported as JSON for automated analysis.

Every instrumented program prints a performance report automatically when executed with the hotpath feature enabled.

cargo run --features=hotpath

Use --features='hotpath,hotpath-alloc' to print memory usage report:

cargo run --features='hotpath,hotpath-alloc'

Enable JSON output by setting HOTPATH_JSON=true.

Live TUI dashboard

Best for long-running processes like HTTP servers, or background workers. It continuously displays functions performance, allocation counters, and channel/stream throughput while the application is running. This mode helps diagnose runtime bottlenecks, queue buildup, and data flow issues that are not visible in static summaries.

Install the TUI with:

cargo install hotpath --features=tui

Run the dashboard:

hotpath console

Then launch your instrumented application (with hotpath feature enabled) in a separate terminal to see live performance metrics.

You can learn how to how to instrument any Rust program in the next sections.