On Fri, 29 Jul 2022 09:34:53 GMT, Aleksey Shipilev <sh...@openjdk.org> wrote:
>> See the bug for symptoms and rationale. >> >> In short, after [JDK-8288396](https://bugs.openjdk.org/browse/JDK-8288396) >> moved the timestamp to `CFLAGS_VM_VERSION` macro, which changes with every >> build, we get Hotspot recompilation every time, even when Hotspot is not >> modified. >> >> I believe current behavior is correct for `--with-source-date=updated` >> (current default): you do Hotspot build, you get updated build timestamp, >> which forces recompilation of affected compilation units, relinkage, >> re-creation of jmods/jimage. The way out is to switch to >> `--with-source-date=current`, which would only get the build timestamp at >> configure time. >> >> CIs and build farms are likely reconfiguring before every build anyway, so >> their behavior is unlikely to be affected. But this switch definitely >> improves the day-to-day OpenJDK development work: it saves >50 seconds on >> every `make` for my machine, see below. >> >> Back-to-back unmodified build before: >> >> >> $ CONF=linux-x86_64-server-release time make hotspot >> Building target 'hotspot' in configuration 'linux-x86_64-server-release' >> Finished building target 'hotspot' in configuration >> 'linux-x86_64-server-release' >> >> 39.03user 10.97system 0:56.89elapsed 87%CPU (0avgtext+0avgdata >> 2048944maxresident)k >> 363616inputs+4108072outputs (484major+1100154minor)pagefaults 0swaps >> >> $ CONF=linux-x86_64-server-release time make hotspot >> Building target 'hotspot' in configuration 'linux-x86_64-server-release' >> Finished building target 'hotspot' in configuration >> 'linux-x86_64-server-release' >> >> 38.18user 9.02system 0:49.18elapsed 95%CPU (0avgtext+0avgdata >> 2048788maxresident)k >> 40inputs+4101112outputs (0major+1100077minor)pagefaults 0swaps >> >> >> Back-to-back unmodified build after: >> >> >> $ CONF=linux-x86_64-server-release time make hotspot >> Building target 'hotspot' in configuration 'linux-x86_64-server-release' >> Finished building target 'hotspot' in configuration >> 'linux-x86_64-server-release' >> >> 2.15user 0.22system 0:02.59elapsed 91%CPU (0avgtext+0avgdata >> 49480maxresident)k >> 0inputs+176outputs (0major+55506minor)pagefaults 0swaps >> >> $ CONF=linux-x86_64-server-release time make hotspot >> Building target 'hotspot' in configuration 'linux-x86_64-server-release' >> Finished building target 'hotspot' in configuration >> 'linux-x86_64-server-release' >> >> 2.18user 0.14system 0:02.46elapsed 94%CPU (0avgtext+0avgdata >> 49332maxresident)k > > Aleksey Shipilev has updated the pull request with a new target base due to a > merge or a rebase. The incremental webrev excludes the unrelated changes > brought in by the merge/rebase. The pull request contains three additional > commits since the last revision: > > - Missed the spot > - Merge branch 'master' into JDK-8290466-default-source-date-current > - Fix Entering the week with faster builds. ------------- PR: https://git.openjdk.org/jdk/pull/9638
