1Local developer settings 2======================== 3 4The first invocation of any task in Lucene's gradle build will generate 5and save a project-local 'gradle.properties' file. This file contains 6the defaults you may (but don't have to) tweak for your particular hardware 7(or taste). Note there are certain settings in that file that may 8be _required_ at runtime for certain plugins (an example is the spotless/ 9google java format plugin, which requires adding custom exports to JVM modules). Gradle 10build only generates this file if it's not already present (it never overwrites 11the defaults) -- occasionally you may have to manually delete (or move) this 12file and regenerate from scratch. 13 14This is an overview of some settings present in gradle.properties. 15 16Parallelism 17----------- 18 19Gradle build can run tasks in parallel but by default it consumes all CPU cores which 20is too optimistic a default for Lucene tests. You can disable the parallelism 21entirely or assign it a 'low' priority with these properties: 22 23org.gradle.parallel=[true, false] 24org.gradle.priority=[normal, low] 25 26The default level of parallelism is computed based on the number of cores on 27your machine (on the first run of gradle build). By default these are fairly conservative 28settings (half the number of cores for workers, for example): 29 30org.gradle.workers.max=[X] 31tests.jvms=[N <= X] 32 33The number of test JVMs can be lower than the number of workers: this just means 34that two projects can run tests in parallel to saturate all the workers. The I/O and memory 35bandwidth limits will kick in quickly so even if you have a very beefy machine bumping 36it too high may not help. 37 38You can always override these settings locally using command line as well: 39gradlew -Ptests.jvms=N --max-workers=X 40 41Test JVMS 42--------- 43 44Test JVMs have their own set of arguments which can be customized. These are configured 45separately from the gradle workers, for example: 46 47tests.jvms=3 48tests.heapsize=512m 49tests.minheapsize=512m 50tests.jvmargs=-XX:+UseParallelGC -XX:TieredStopAtLevel=1 51 52Gradle Daemon 53------------- 54 55The gradle daemon is a background process that keeps an evaluated copy of the project 56structure, some caches, etc. It speeds up repeated builds quite a bit but if you don't 57like the idea of having a (sizeable) background process running in the background, 58disable it. 59 60org.gradle.daemon=[true, false] 61org.gradle.jvmargs=... 62 63