> `jmod`/`jlink` are executed during build time to produce the `jmod` and the > base modules image. On slow hardware (Raspberry Pi -class, for example) > and/or slow VMs (debug, interpreter-only, for example) this takes a while. > Profiling shows the considerable time is spent on hashing modules either for > writing out the ModuleHash attribute or for verifying the hashes are good. > > Those paths can be parallelized to make them quite faster. > > The major contributors to module hashing are `java.base`, `jdk.desktop` and > `jdk.localedata`, so we have a significant opportunity for parallelism here. > > Motivational improvements on `make clean-images images`: > > > # x86_64 Server, release > > # Baseline > real 0m11.895s > user 1m4.526s > sys 0m10.715s > > # Patched > real 0m10.701s ; <--- 1.1x improvement > user 1m5.097s > sys 0m11.260s > > # x86_64 Zero, release > > # Baseline > real 5m20.335s > user 7m7.791s > sys 0m7.258s > > # Patched > real 2m23.551s ; <--- 2.23x improvement > user 7m14.442s > sys 0m7.856s > > > Additional testing: > - [x] Linux x86_64 fastdebug, `java/util/jar` > - [x] Linux x86_64 fastdebug, `tools/jmod` > - [x] Linux x86_64 fastdebug, `tools/jlink` > - [x] Linux x86_64 fastdebug `tier1`
Aleksey Shipilev has updated the pull request incrementally with one additional commit since the last revision: Touchups ------------- Changes: - all: https://git.openjdk.org/jdk/pull/10060/files - new: https://git.openjdk.org/jdk/pull/10060/files/877ff17d..2389fdfd Webrevs: - full: https://webrevs.openjdk.org/?repo=jdk&pr=10060&range=01 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=10060&range=00-01 Stats: 5 lines in 2 files changed: 0 ins; 2 del; 3 mod Patch: https://git.openjdk.org/jdk/pull/10060.diff Fetch: git fetch https://git.openjdk.org/jdk pull/10060/head:pull/10060 PR: https://git.openjdk.org/jdk/pull/10060
