next.js

49dd9035 - bench: add A/B branch comparison workflow to BENCHMARKING.md (#92721)

bench: add A/B branch comparison workflow to BENCHMARKING.md (#92721) ## What Adds a new "A/B branch comparison" section to `bench/BENCHMARKING.md` with practical guidance for comparing benchmark results across two branches. ## Why From running benchmarks comparing canary vs PR #92678, we identified several patterns that lead to noisy or misleading results: - Running the full route suite when only one route shows signal wastes time (~3 min per run) - The default 120 serial requests is too noisy for sub-2ms routes - Single runs can swing 10-15% on light routes - Percentage deltas from a single pair of runs can be misleading without absolute numbers ## What's in the new section - Start with a focused route, not the full suite - Increase request counts for fast routes (500 serial / 5000 load) - Run at least 3 times per side to average out noise - Compare absolute req/s, not just deltas - Watch for system state drift between runs - Full example workflow with checkout/build/run loop <!-- NEXT_JS_LLM_PR -->