vLLM RFC #17419: 'Kernel Library Restructure / Packaging Split (addressing long build times)'

Filed 2025-04-29, still OPEN as of 2026-10-04 - the build-time problem has not been structurally solved. Two hard numbers: (a) 'On CI the wall clock time for a build (with no cache) exceeds 5 hours', citing a Buildkite build; (b) '95% [of commits in the last year] did not modify the csrc directory', i.e. the kernel tree - the only part that requires compilation - is untouched by the overwhelming majority of commits, so the build cost is paid far more often than it is changed. Also records that the project itself acknowledges the build time in its install-from-source docs and points contributors at Python-only builds.