# Guidelines for JVM layer (OpenJDK)

When starting a new JVM optimization, the following is a list of recommended parameters. After having selected the parameters, always make sure to add/review the corresponding parameter domains and constraints based on your environment. Please refer to the optimization pack reference page for more information.

## Suggested Parameters for Open JDK 11 <a href="#suggested-parameters" id="suggested-parameters"></a>

* `jvm_maxHeapSize`
* `jvm_minHeapSize`
* `jvm_gcType`
* `jvm_newSize`
* `jvm_survivorRatio`
* `jvm_maxTenuringThreshold`
* `jvm_parallelGCThreads`
* `jvm_concurrentGCThreads`
* `jvm_maxInlineSize`
* `jvm_inlineSmallCode`
* `jvm_useTransparentHugePages`
* `jvm_alwaysPreTouch`

## Suggested Parameters for Open JDK 8 <a href="#suggested-parameters" id="suggested-parameters"></a>

When starting a new JVM optimization, the following is a list of recommended parameters to include in your study:

* `jvm_gcType`
* `jvm_maxHeapSize`
* `jvm_newSize`
* `jvm_survivorRatio`
* `jvm_maxTenuringThreshold`
* `jvm_parallelGCThreads`
* `jvm_concurrentGCThreads`