Hi all, I've been profiling Maven 4 RC6 on a large reactor (4,383 modules, diamond-graph, generated with maven-multiproject-generator) as several performance regressions were found during in the vote thread compared to Maven 3. A clean install -DskipTests that takes ~1:15 on Maven 3.9.16 was taking ~2:45 on Maven 4 RC6.
After a series of JFR-guided optimizations across 4 repositories, Maven 4 now completes the same build in ~1:18 — at parity with Maven 3. Benchmark (Apple M4 Pro, JDK 21): | Configuration | Wall time | |----------------------------|----------------| | Maven 3.9.16 | 1:14 – 1:18 | | Maven 4 RC6 (unpatched) | 2:45 | | + all optimizations | 1:18 | The full analysis (JFR hotspots, root causes, complexity reductions) and all 8 PRs are tracked in: https://github.com/apache/maven/issues/12667 The main wins are: 1. Switching the default conflict resolver from classic (O(N²)) to path (O(N)) — single biggest win, 2:45 → 1:45 2. TransitiveDependencyManager optimizations — instance reuse, cons-list parent pointer, varargs elimination 3. Reactor sort O(N² log N) → O(N log N), model building pipeline allocation reduction 4. Install/Deploy plugin O(N²) reactor scans → O(N) with caching All PRs are green and ready for review. Regards, Guillaume
