Optimizing Cpp Performance

Optimizing C++ Performance

Profile an optimized, symbolized, production-like build. Explain allocations, indirection, dispatch, and generated code before introducing a low-level optimization.

1. Read C++ performance audit.
2. Scan for temporary strings, shared ownership, virtual/interface dispatch, std::function, map/tree lookup, pointer-rich storage, accidental copies, and lock contention.
3. Treat views, arenas/pmr, aliasing, SIMD, LTO/PGO, and branch/cold hints as measured, lifetime-safe, portable-by-default decisions—not generic fast paths. For SIMD, compile SSE2/AVX2/NEON intrinsics behind runtime CPU dispatch with a scalar fallback — e.g. a simd.cpp carrying skip_whitespace / scan_identifier_chars / find_line_terminator — never a -march-pinned distributable that assumes the build host's ISA when it ships to CPUs you do not control. Pin -march only to a floor a controlled target guarantees, and record why. Enforced by scripts/fleet/check/build-microarch-is-portable.mts.
4. For a Node boundary, also read optimizing-node-native-performance.