diff --git a/README.md b/README.md index 34e13b6ea7d..3c3f0136623 100644 --- a/README.md +++ b/README.md @@ -221,6 +221,13 @@ The following options should be set with a `-P` switch, for example `./gradlew - * `enableTestCoverage`: enables test coverage plugins and tasks, including bytecode enhancement of classes required to track said coverage. Note that this introduces some overhead when running tests and hence why it's disabled by default (the overhead varies, but 15-20% is a reasonable estimate). +* `scalaOptimizerMode`: configures the optimizing behavior of the scala compiler, the value should be one of `none`, `method`, `inline-kafka` or +`inline-scala` (the default is `inline-kafka`). `none` is the scala compiler default, which only eliminates unreachable code. `method` also +includes method-local optimizations. `inline-kafka` adds inlining of methods within the kafka packages. Finally, `inline-scala` also +includes inlining of methods within the scala library (which avoids lambda allocations for methods like `Option.exists`). `inline-scala` is +only safe if the Scala library version is the same at compile time and runtime. Since we cannot guarantee this for all cases (for example, users +may depend on the kafka jar for integration tests where they may include a scala library with a different version), we don't enable it by +default. See https://www.lightbend.com/blog/scala-inliner-optimizer for more details. ### Dependency Analysis ### diff --git a/build.gradle b/build.gradle index bf92f9645eb..e9b25123b44 100644 --- a/build.gradle +++ b/build.gradle @@ -134,6 +134,12 @@ ext { userEnableTestCoverage = project.hasProperty("enableTestCoverage") ? enableTestCoverage : false + // See README.md for details on this option and the reasoning for the default + userScalaOptimizerMode = project.hasProperty("scalaOptimizerMode") ? scalaOptimizerMode : "inline-kafka" + def scalaOptimizerValues = ["none", "method", "inline-kafka", "inline-scala"] + if (!scalaOptimizerValues.contains(userScalaOptimizerMode)) + throw new GradleException("Unexpected value for scalaOptimizerMode property. Expected one of $scalaOptimizerValues), but received: $userScalaOptimizerMode") + generatedDocsDir = new File("${project.rootDir}/docs/generated") commitId = project.hasProperty('commitId') ? commitId : null @@ -515,21 +521,19 @@ subprojects { "-Xlint:unused" ] - // Inline more aggressively when compiling the `core` jar since it's not meant to be used as a library. - // More specifically, inline classes from the Scala library so that we can inline methods like `Option.exists` - // and avoid lambda allocations. This is only safe if the Scala library version is the same at compile time - // and runtime. We cannot guarantee this for libraries like kafka streams, so only inline classes from the - // Kafka project in that case. - List inlineFrom - if (project.name.equals('core')) - inlineFrom = ["-opt-inline-from:scala.**", "-opt-inline-from:kafka.**", "-opt-inline-from:org.apache.kafka.**"] - else - inlineFrom = ["-opt-inline-from:org.apache.kafka.**"] + // See README.md for details on this option and the meaning of each value + if (userScalaOptimizerMode.equals("method")) + scalaCompileOptions.additionalParameters += ["-opt:l:method"] + else if (userScalaOptimizerMode.startsWith("inline-")) { + List inlineFrom = ["-opt-inline-from:org.apache.kafka.**"] + if (project.name.equals('core')) + inlineFrom.add("-opt-inline-from:kafka.**") + if (userScalaOptimizerMode.equals("inline-scala")) + inlineFrom.add("-opt-inline-from:scala.**") - // Somewhat confusingly, `-opt:l:inline` enables all optimizations. `inlineFrom` configures what can be inlined. - // See https://www.lightbend.com/blog/scala-inliner-optimizer for more information about the optimizer. - scalaCompileOptions.additionalParameters += ["-opt:l:inline"] - scalaCompileOptions.additionalParameters += inlineFrom + scalaCompileOptions.additionalParameters += ["-opt:l:inline"] + scalaCompileOptions.additionalParameters += inlineFrom + } if (versions.baseScala != '2.12') { scalaCompileOptions.additionalParameters += ["-opt-warnings", "-Xlint:strict-unsealed-patmat"]