Evaluate Profile-Guided Optimization (PGO)

[zamazan4ik]

Hi!

Recently I did many Profile-Guided Optimization (PGO) benchmarks on multiple projects (including many databases like PostgreSQL, MongoDB, Redis, and many others) - the results are available here, all databases results are located here. So that's why I think it's worth trying to apply PGO to Age.

I can suggest the following things to do:

• Evaluate PGO's applicability and benchmark results to Age.
• If PGO helps to achieve better performance - add a note to Age's documentation about that. In this case, users and maintainers will be aware of another optimization opportunity for Age.
• Provide PGO integration into the build scripts. It can help users and maintainers easily apply PGO for their own workloads.
• PGO-optimize prebuilt Age binaries (if it's possible to prepare a generic-enough test workload), if you have such binaries.

Here are some PGO integration examples in the existing build scripts in other projects:

• Rustc: a CI script for the multi-stage build
• GCC:
  • Official docs, section "Building with profile feedback" (even AutoFDO build is supported)
  • A part in a "wonderful" configure script
• Clang: Docs
• Python:
  • CPython: README
  • Pyston: README
• Go: Bash script
• V8: Bazel flag
• ChakraCore: Scripts
• Chromium: Script
• Firefox: Docs
  • Thunderbird has PGO support too
• PHP - Makefile command and old Centminmod scripts
• MySQL: CMake script
• YugabyteDB: GitHub commit
• FoundationDB: Script
• Zstd: Makefile
• Foot: Scripts
• Windows Terminal: GitHub PR
• Pydantic-core: GitHub PR

Some PGO documentation examples:

• ClickHouse: https://clickhouse.com/docs/en/operations/optimizing-performance/profile-guided-optimization
• Databend: https://databend.rs/doc/contributing/pgo
• Vector: https://vector.dev/docs/administration/tuning/pgo/
• Nebula: https://docs.nebula-graph.io/3.5.0/8.service-tuning/enable_autofdo_for_nebulagraph/
• GCC: Official docs, section "Building with profile feedback" (even AutoFDO build is supported)
• Clang:
  • https://llvm.org/docs/HowToBuildWithPGO.html
  • https://llvm.org/docs/AdvancedBuilds.html

After PGO, I can suggest evaluating LLVM BOLT as an additional optimization step after PGO.