I have been looking into `make clean-images images` performance, and realized jmod keeps compressing files with default compression level. Tuning that toward lighter compression levels improves build performance considerably, without a heavy loss in *.jmod sizes.
This PR allows JMOD to select the compression level. Follow-ups would use this in the build system. This change nominally requires CSR, but I would like to gauge the reaction to this patch first, before submitting a formal CSR. The interesting asymmetry against `jlink` is: `jlink` provides `--compress` option that only takes `2` for "ZIP compression". I would argue it would be beneficial to add `--compression-level` to `jlink` as well, so to select the compression level there too. ------------- Commit messages: - Fix Changes: https://git.openjdk.org/jdk/pull/10213/files Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=10213&range=00 Issue: https://bugs.openjdk.org/browse/JDK-8293499 Stats: 99 lines in 4 files changed: 92 ins; 0 del; 7 mod Patch: https://git.openjdk.org/jdk/pull/10213.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10213/head:pull/10213 PR: https://git.openjdk.org/jdk/pull/10213
