Rsbuild performance profiling

Workflow

1. Define the target scenario before collecting data:

   • operation: build, dev startup, rebuild, request serving, memory usage, or another explicit flow
   • benchmark project or fixture
   • metric: wall time, CPU time, self time, allocations, RSS, heap
   • success threshold, if the user provided one

2. Record the baseline first. Keep runtime, package manager, dependencies, environment variables, command flags, and input project unchanged for comparisons.

3. Save raw artifacts when available, such as CPU profiles, heap snapshots, logs, timing output, and benchmark commands. Do not rely only on subjective observations.

4. Separate costs by ownership: