Enable --compile-zinc-use-classpath-jars by default #4525
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
wisechengyi
approved these changes
Apr 27, 2017
thesamet
pushed a commit
to thesamet/pants
that referenced
this pull request
May 9, 2017
### Problem According to Twitter's internal benchmark suite, the `--compile-zinc-use-classpath-jars` (ie: "use zjars") option used to effectively disable incremental compile by causing entire classpath entries to be invalidated. But it looks like the `zinc` `1.0.0-X` upgrade (in November, approximately) removed this limitation: zinc now correctly tracks changes in classpath jars, without fully invalidating downstream targets. ### Solution Enable `--compile-zinc-use-classpath-jars` by default, and deprecate the option. ### Result JVM compiles should be 20%-40% faster on rotational drives (anecdotally, the impact is less pronounced on SSDs). Additionally, further improvements might be possible now that loose classfiles only need to be present _during_ a compile (see pantsbuild#4524).
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
Problem
According to Twitter's internal benchmark suite, the
--compile-zinc-use-classpath-jars(ie: "use zjars") option used to effectively disable incremental compile by causing entire classpath entries to be invalidated.But it looks like the
zinc1.0.0-Xupgrade (in November, approximately) removed this limitation: zinc now correctly tracks changes in classpath jars, without fully invalidating downstream targets.Solution
Enable
--compile-zinc-use-classpath-jarsby default, and deprecate the option.Result
JVM compiles should be 20%-40% faster on rotational drives (anecdotally, the impact is less pronounced on SSDs). Additionally, further improvements might be possible now that loose classfiles only need to be present during a compile (see #4524).