Ruff Author Finds ThinLTO Dramatically Speeds Up PGO Builds

Charlie Marsh, author of Ruff and Uv, found that using thin LTO instead of fat LTO when building instrumented binaries for PGO dramatically cuts build time with almost no performance loss. He confirmed experimentally that both produce equally valid PGO profiling data.

2026-10-10 ~ 2026-10-10 · 4 related posts

• Ruff author: ThinLTO on PGO instrumented builds cuts build time with no perf cost — charliermarsh · 2026-10-10
• Thin and fat LTO share the same pre-link pipeline, keeping PGO counts intact — charliermarsh · 2026-10-10
• Testing confirms thin and fat LTO produce equivalently useful PGO data — charliermarsh · 2026-10-10

1 near-duplicate retellings: charliermarsh