JRuby master configuration properties.

gistfile1.txt

These properties can be used to alter runtime behavior for perf or compatibility.
Specify them by passing -X<property>=<value>
  or if passing directly to Java, -Djruby.<property>=<value>
  or put <property>=<value> in .jrubyrc

compiler settings:

   compile.mode=[JIT, FORCE, OFF]
      Set compilation mode. JIT = at runtime; FORCE = before execution. Default is JIT.
   compile.dump=[true, false]
      Dump to console all bytecode generated at runtime. Default is false.
   compile.threadless=[true, false]
      (EXPERIMENTAL) Turn on compilation without polling for "unsafe" thread events. Default is false.
   compile.dynopt=[true, false]
      (EXPERIMENTAL) Use interpreter to help compiler make direct calls. Default is false.
   compile.fastops=[true, false]
      Turn on fast operators for Fixnum and Float. Default is false.
   compile.chainsize=[Integer]
      Set the number of lines at which compiled bodies are "chained". Default is 500.
   compile.lazyHandles=[true, false]
      Generate method bindings (handles) for compiled methods lazily. Default is false.
   compile.peephole=[true, false]
      Enable or disable peephole optimizations. Default is true.
   compile.noguards=[true, false]
      Compile calls without guards, for experimentation. Default is false.
   compile.fastest=[true, false]
      Compile with all "mostly harmless" compiler optimizations. Default is false.
   compile.fastsend=[true, false]
      Compile obj.send(:sym, ...) as obj.sym(...). Default is false.
   compile.inlineDyncalls=[true, false]
      Emit method lookup + invoke inline in bytecode. Default is false.
   compile.fastMasgn=[true, false]
      Return true from multiple assignment instead of a new array. Default is false.
   compile.invokedynamic=[true, false]
      Use invokedynamic on Java 7+. Default is true.

invokedynamic settings:

   invokedynamic.maxfail=[Integer]
      Maximum size of invokedynamic PIC. Default is 2.
   invokedynamic.log.binding=[true, false]
      Log binding of invokedynamic call sites. Default is false.
   invokedynamic.log.constants=[true, false]
      Log invokedynamic-based constant lookups. Default is false.
   invokedynamic.all=[true, false]
      Enable all possible uses of invokedynamic. Default is false.
   invokedynamic.safe=[true, false]
      Enable all safe (but maybe not fast) uses of invokedynamic. Default is false.
   invokedynamic.invocation=[true, false]
      Enable invokedynamic for method invocations. Default is true.
   invokedynamic.invocation.switchpoint=[true, false]
      Use SwitchPoint for class modification guards on invocations. Default is true.
   invokedynamic.invocation.indirect=[true, false]
      Also bind indirect method invokers to invokedynamic. Default is true.
   invokedynamic.invocation.java=[true, false]
      Bind Ruby to Java invocations with invokedynamic. Default is false.
   invokedynamic.invocation.attr=[true, false]
      Bind Ruby attribue invocations directly to invokedynamic. Default is true.
   invokedynamic.invocation.fastops=[true, false]
      Bind Fixnum and Float math using optimized logic. Default is true.
   invokedynamic.cache=[true, false]
      Use invokedynamic to load cached values like literals and constants. Default is true.
   invokedynamic.cache.constants=[true, false]
      Use invokedynamic to load constants. Default is false.
   invokedynamic.cache.literals=[true, false]
      Use invokedynamic to load literals. Default is true.

jit settings:

   jit.threshold=[Integer]
      Set the JIT threshold to the specified method invocation count. Default is 50.
   jit.max=[Integer]
      Set the max count of active methods eligible for JIT-compilation. Default is 4096.
   jit.maxsize=[Integer]
      Set the maximum full-class byte size allowed for jitted methods. Default is 30000.
   jit.logging=[true, false]
      Enable JIT logging (reports successful compilation). Default is false.
   jit.logging.verbose=[true, false]
      Enable verbose JIT logging (reports failed compilation). Default is false.
   jit.dumping=[true, false]
      Enable stdout dumping of JITed bytecode. Default is false.
   jit.logEvery=[Integer]
      Log a message every n methods JIT compiled. Default is 0.
   jit.exclude=[ClsOrMod, ClsOrMod::method_name, -::method_name]
      Exclude methods from JIT. Comma delimited. Default is none.
   jit.cache=[true, false]
      Cache jitted method in-memory bodies across runtimes and loads. Default is true.
   jit.codeCache=[dir]
      Save jitted methods to <dir> as they're compiled, for future runs. Default is null.
   jit.debug=[true, false]
      Log loading of JITed bytecode. Default is false.

intermediate representation settings:

   ir.debug=[true, false]
      Debug generation of JRuby IR. Default is false.
   ir.compiler.debug=[true, false]
      Debug compilation of JRuby IR. Default is false.
   ir.pass.live_variable=[true, false]
      Enable live variable analysis of IR. Default is false.
   ir.pass.dead_code=[true, false]
      Enable dead code elimination in IR. Default is false.
   ir.pass.test_inliner=[String]
      Use specified class for inlining pass in IR. Default is none.

native settings:

   native.enabled=[true, false]
      Enable/disable native code, including POSIX features and C exts. Default is true.
   native.verbose=[true, false]
      Enable verbose logging of native extension loading. Default is false.
   cext.enabled=[true, false]
      Enable or disable C extension support. Default is true.
   ffi.compile.dump=[true, false]
      Dump bytecode-generated FFI stubs to console. Default is false.
   ffi.compile.threshold=[Integer]
      Number of FFI invocations before generating a bytecode stub. Default is 100.
   ffi.compile.invokedynamic=[true, false]
      Use invokedynamic to bind FFI invocations. Default is false.

thread pooling settings:

   thread.pool.enabled=[true, false]
      Enable reuse of native threads via a thread pool. Default is false.
   thread.pool.min=[Integer]
      The minimum number of threads to keep alive in the pool. Default is 0.
   thread.pool.max=[Integer]
      The maximum number of threads to allow in the pool. Default is 2147483647.
   thread.pool.ttl=[Integer]
      The maximum number of seconds to keep alive an idle thread. Default is 60.

miscellaneous settings:

   compat.version=[1.8, 1.9]
      Specify the major Ruby version to be compatible with. Default is 1.8.
   objectspace.enabled=[true, false]
      Enable or disable ObjectSpace.each_object. Default is false.
   launch.inproc=[true, false]
      Set in-process launching of e.g. system('ruby ...'). Default is false.
   bytecode.version=[1.5, 1.6, 1.7]
      Specify the major Ruby version to be compatible with. Default is 1.6.
   management.enabled=[true, false]
      Set whether JMX management is enabled. Default is false.
   jump.backtrace=[true, false]
      Make non-local flow jumps generate backtraces. Default is false.
   process.noUnwrap=[true, false]
      Do not unwrap process streams (issue on some recent JVMs). Default is false.
   reify.classes=[true, false]
      Before instantiation, stand up a real Java class for ever Ruby class. Default is false.
   reify.logErrors=[true, false]
      Log errors during reification (reify.classes=true). Default is false.
   reflected.handles=[true, false]
      Use reflection for binding methods, not generated bytecode. Default is false.
   backtrace.color=[true, false]
      Enable colorized backtraces. Default is false.
   backtrace.style=[normal, raw, full, mri, rubinius]
      Set the style of exception backtraces. Default is normal.
   thread.dump.signal=[USR1, USR2, etc]
      Set the signal used for dumping thread stacks. Default is USR2.
   native.net.protocol=[true, false]
      Use native impls for parts of net/protocol. Default is false.
   fiber.coroutines=[true, false]
      Use JVM coroutines for Fiber. Default is false.

debugging and logging settings:

   debug.loadService=[true, false]
      Log require/load file searches. Default is false.
   debug.loadService.timing=[true, false]
      Log require/load parse+evaluate times. Default is false.
   debug.launch=[true, false]
      Log externally-launched processes. Default is false.
   debug.fullTrace=[true, false]
      Set whether full traces are enabled (c-call/c-return). Default is false.
   debug.scriptResolution=[true, false]
      Print which script is executed by '-S' flag. Default is false.
   errno.backtrace=[true, false]
      Generate backtraces for heavily-used Errno exceptions (EAGAIN). Default is false.
   log.exceptions=[true, false]
      Log every time an exception is constructed. Default is false.
   log.backtraces=[true, false]
      Log every time an exception backtrace is generated. Default is false.
   log.callers=[true, false]
      Log every time a Kernel#caller backtrace is generated. Default is false.
   logger.class=[class name]
      Use specified class for logging. Default is org.jruby.util.log.JavaUtilLoggingLogger.

java integration settings:

   ji.setAccessible=[true, false]
      Try to set inaccessible Java methods to be accessible. Default is true.
   ji.upper.case.package.name.allowed=[true, false]
      Allow Capitalized Java pacakge names. Default is false.
   interfaces.useProxy=[true, false]
      Use java.lang.reflect.Proxy for interface impl. Default is false.
   java.handles=[true, false]
      Use generated handles instead of reflection for calling Java. Default is false.
   ji.newStyleExtension=[true, false]
      Extend Java classes without using a proxy object. Default is false.
   ji.objectProxyCache=[true, false]
      Cache Java object wrappers between calls. Default is true.