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• -XX:EnableMVT
  Boolean value, default value is `false`
  If true enable support for minimal value types with a value capable class and an associated derived value type.
• -XX:EnableValhalla
  Boolean value, default value is `false`
  If true enable support for "valhalla" value types, which in contrast to MVT supports direct value types in conjunction with byte code generation or with the javac flag "enableValueTypes".
• -XX:ValueTypePassFieldsAsArgs
  Boolean value, default value is `true`
  Pass each value type field as an argument to a method call instead of a value type reference
• -XX:ValueTypeReturnedAsFields
  Boolean value, default value is `true`
  Return value type fields instead of a value type reference
• -XX:ValueArrayFlatten
  Boolean value, default value is `true`
  Flatten arrays of values, if possible
• -XX:ValueArrayElemMaxFlatSize
  Integer value, default is -1
  Max size for flattening an array of values, < 0 means no limit
• -XX:ValueArrayElemMaxFlatOops
  Integer value, default is 4
  Max number of embedded object references in value type to flatten in an array, < 0 means no limit 
• -XX:ValueArrayAtomicAccess
  Boolean value, default value is `false`
  Enable atomic access to values in an array

To determine if there are unwanted allocations (boxing) see the flags:

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