Summary

Optimizes turbo run --dry wall-clock time by up to 1.48x on large monorepos by eliminating redundant file hashing work and removing a serialization bottleneck in globwalk operations.

Benchmarks

Tested across three repos of varying size:

The improvement scales with repo size — specifically with how many tasks share the same (package, inputs) combination.

Changes

File hash deduplication — Multiple tasks in the same package with identical inputs config (e.g. build, lint, typecheck all in one package) previously each ran an independent globwalk + file hash computation. Now tasks are grouped by (package_path, globs, include_default) and each unique combination is computed once, with results shared across tasks.

Parallel globwalks via retry-on-EMFILE — The previous IoSemaphore (max=1) serialized all globwalk operations to prevent fd exhaustion, making this the dominant bottleneck on large repos. This replaces the semaphore with retry-with-exponential-backoff on EMFILE errors (the same pattern Node's graceful-fs uses), allowing globwalks to run fully parallel on rayon. If the OS returns "too many open files", the operation sleeps briefly and retries — up to 10 times with exponential backoff capped at 1s.

Zero-copy lockfile dependency lookups — Lockfile::all_dependencies now returns Cow<'_, HashMap<String, String>> instead of cloning the HashMap on every call. For pnpm (which pre-builds a dependency index), this eliminates ~329k HashMap clones during transitive closure resolution.

Optimized transitive closure cache keys — The DashMap resolve cache now uses a single null-byte-separated String key built into a reusable buffer, instead of allocating a (String, String, String) tuple per lookup.

HashMap importers for pnpm — Converted pnpm's importers field from BTreeMap to HashMap (with sorted serialization) for O(1) workspace lookups during resolve_package.