Home
Jikes RVM (Research Virtual Machine) provides a flexible open testbed to prototype virtual machine technologies and experiment with a large variety of design alternatives. The system is licensed under an OSI approved license. Jikes RVM runs on many platforms and advances the state-of-the-art of virtual machine technologies for dynamic compilation, adaptive optimization, garbage collection, thread scheduling, and synchronization. A distinguishing characteristic of Jikes RVM is that it is implemented in the Java™ programming language and is self-hosted i.e., its Java code runs on itself without requiring a second virtual machine. Most other virtual machines for the Java platform are written in native code (typically, C or C++). A Java implementation provides ease of portability, and a seamless integration of virtual machine and application resources such as objects, threads, and operating-system interfaces.
Many researchers have found that Jikes RVM provides a useful vehicle for research on the frontiers of virtual machine technologies (over 150 publications and 27 dissertations), as well as teaching courses. If you are looking for where to start reading about the Jikes RVM we have a recommended reading page.
News
We're very proud to announce that Jikes RVM version 2.9.3 is now available for download! It's been a little bit longer than usual since the last release and there's been quite a bit of activity on the project and improvements to the system. The appended release notes capture many of the highlights; for more details see the hyperlinked version in JIRA (http://jira.codehaus.org/browse/RVM/fixforversion/13726).
The release is available at http://downloads.sourceforge.net/jikesrvm/jikesrvm-2.9.3.tar.bz2.
** Bug
* [RVM-196] - VM_Processor not assignable with VM_GreenScheduler
* [RVM-314] - Support for Java 1.4 assertions
* [RVM-315] - java.lang.Method.invoke changes the parameters
* [RVM-316] - A Null pointer for the UTF8CHARSET in java.util.zip.ZipFile$PartialInputStream
* [RVM-326] - Failing basic tests don't signal failure
* [RVM-330] - Thread.sleep() does not handle interrupts correctly
* [RVM-339] - Image bloat (code +25% & data +5%)
* [RVM-340] - Annotations don't handle arrays of primitive types correctly
* [RVM-342] - NPE with advice files
* [RVM-347] - PPC 64 regressions and Intel stress regressions since the introduction of read barriers
* [RVM-351] - Javac regression
* [RVM-352] - Running many iterations of _200_check fails floating point remainder test
* [RVM-353] - Production Opt 0 builds broken
* [RVM-355] - Complete SPEC JVM with 20 iterations dies in GC
* [RVM-357] - Fatal error when synchronising on null objects
* [RVM-365] - PPC (AIX) Stack Scanning Appears Broken
* [RVM-368] - Compiler confusion over equal but non-identical objects
* [RVM-374] - Static field allocation is non-deterministic
* [RVM-380] - We create a lot (15909) optimization plan atomic elements using 572724bytes in the boot image
* [RVM-383] - Branch likely and unlikely prefixes show up as LOCK prefixes in x86 disassembler output
* [RVM-394] - Tune inlining of arraycopy
* [RVM-412] - Latent branch optimization bug when maximizing blocks
* [RVM-424] - Multianewarray confusion in opt compiler
* [RVM-439] - OSR triggering code misuses suspend/resume
* [RVM-447] - Inline size estimation reduction factor calculation over rates precise information causing bloat and slow down
* [RVM-452] - Off-by-one error in "VMField.checkReadAccess" and "VM.checkWriteAccess"
* [RVM-456] - Clean build broken
* [RVM-464] - Opt compiler ldc_w for class literal broken
* [RVM-466] - Four tests in test run "tiny" fail when compiled with -X:aos:initial_compiler=opt -X:aos:enable_recompilation=false
* [RVM-467] - BURS performing illegal reordering to before PEI
* [RVM-468] - Instanceof test differs in opt compiler from baseline for instanceof/checkcast of magic[][]
* [RVM-478] - Redesign AIX native method Linkage conventions to protect CMID field from being smashed by native code saved CR
** Improvement
* [RVM-81] - Annotations in java.lang classes
* [RVM-195] - Enable inlining of @Pure methods
* [RVM-274] - Remove OPT_ prefix from all opt compiler classes
* [RVM-276] - opt compiler package structure
* [RVM-304] - Improve performance of chacter encoder when encoding to and from arrays
* [RVM-305] - Add final annotations to java.io.OutputStreamWriter
* [RVM-308] - Greater use of StringBuilder rather than StringBuffer
* [RVM-309] - Greater use of "<Number>.valueOf" rather than "new <Number>"
* [RVM-310] - Class library fields that could be final aren't final
* [RVM-311] - String toUpperCase and toLowerCase perform a String.equals to see if the Locale is Turkey per invocation
* [RVM-322] - Intel assembler register naming improvement required
* [RVM-331] - Implement support for MMX registers
* [RVM-343] - Support for hardware SQRT instruction
* [RVM-344] - Simplifier rule for square root operator
* [RVM-378] - Avoid replicating field and method vectors
* [RVM-379] - Don't replicate OSR_EncodedOSRMaps
* [RVM-381] - Upgrade to Classpath 0.97
* [RVM-385] - Refactor reflection to use VM interface
* [RVM-387] - Baseline compiler emits RegDisp instructions when the Disp is 0
* [RVM-390] - VM_Statics/JTOC space saving has cost us single iteration fop performance
* [RVM-391] - Assign CPU # to each VM_Processor to have more predictable performance results.
* [RVM-392] - Improvements to ZipEntry
* [RVM-395] - Local common sub-expression elimination of Pure method calls
* [RVM-408] - Simple elimination of stack traces
* [RVM-417] - Switch performance runs to using a profiled image
* [RVM-421] - Pre-allocate 1 set of exception registers for athrow
* [RVM-422] - Update to latest Classpath j.u.c.CopyOnWriteArrayList
* [RVM-431] - Fix processor JNI entry/collector rendezvous race
* [RVM-433] - Increase final fields in java.nio
* [RVM-435] - Don't allocate memory when converting C buffers to Strings or Classes
* [RVM-437] - Integer.toString doesn't keep cache of common values
* [RVM-451] - Structure of code in GNU Classpath java.util.Vector and java.util.Arraylist interacts poorly with inlining
** New Feature
* [RVM-210] - Add Image sizes tracking to Regression report and mailout
* [RVM-319] - Create X10 test harness
* [RVM-406] - Add Immix garbage collector
* [RVM-441] - Sticky mark bits collector
* [RVM-457] - Immix Garbage Collectors
* [RVM-266] - Provide preliminary support for a non-copying unsynchronised StringBuffer implementation
** Task and Sub-task
* [RVM-425] - Implement 2d array helper for PPC baseline
* [RVM-224] - Push OSR-specific fields in VM_NormalMethod to subclass/side data structure
* [RVM-450] - Prevent compilation at max opt level before some dynamic call graph information has been gathered
* [RVM-453] - Testing framework missing failures in basic tests that use diff for sanity.
Congratulations to Georgios Gousios (Athens University of Economics and Business), Byeongcheol Lee (University of Texas in Austin), Filip Pizlo (Purdue University) for being selected to work on Jikes RVM projects for the SoC. Georgios is working on Jikes RVM and JNode integration, Byeongcheol is working on extending debugger support, Filip is looking at extending the threading model.
I'm pleased to announce the Jikes RVM has been accepted into the Google Summer of Code for the 2nd year! We have a range of mentors bringing together experience from the Jikes RVM and related projects. Please have a look at our project proposals and our application template. As with last year, if you think there is an interesting project that should be listed but hasn't been then please feel free to propose it. To better integrate with our bug and feature tracking system we would much prefer if such proposals could also be added in to our issue tracker. We look forward to interest from prospective students! Don't forget the deadline for applications is March 31st.
Jikes RVM (nee Jalapeno) turned 10 years old last week! The first lines of code in what became Jikes RVM were written by Derek Lieber on Nov 21, 1997.
We're very proud to announce that Jikes RVM version 2.9.2 is now available for download. As you can see from the appended release notes, there's been quite a bit of activity on the project since 2.9.1!
The release is available at http://downloads.sourceforge.net/jikesrvm/jikesrvm-2.9.2.tar.bz2.
New Features
- [RVM-121] - Separate code space for dynamically generated code
- [RVM-231] - Alignment checking (for IA32 and debugging purposes only)
Improvements
- [RVM-16] - Constant folding values from TIBs produces failures
- [RVM-27] - float/double to int/long conversions are overly expensive
- [RVM-51] - Switch from pthread hijacking back to portable native sync for gtk AWT threading
- [RVM-54] - Switch to Claspath's java.lang.Thread
- [RVM-64] - Flexible thread model
- [RVM-82] - Exceptions in Uninterruptible code should result in immediate fatal errors
- [RVM-94] - Enable SSE C/C++ compiler flags
- [RVM-164] - Use clock_gettime to implement sysNanoTime
- [RVM-179] - Move java/lang/String out of libraryInterface and into a patch against Classpath
- [RVM-185] - Reduce cost of ThreadLocal(s) to improve Jython performance
- [RVM-189] - Use will never move information from MM_Interface when generating constant operands
- [RVM-191] - Improve inline size estimator in VM_NormalMethod to account for getstatic of final primitive fields being folded by opt compiler
- [RVM-218] - Use VM_Magic.pause in spinwait loops
- [RVM-285] - Switch AOS call graph profiling to use CBS framework from Arnold & Grove 2005
Bug Fixes
- [RVM-55] - A thread that is interrupted prior to being scheduled won't interrupt
- [RVM-62] - Interrupted exceptions are generated in the caller of Thread.interrupt instead of by the thread throwing the interrupted exception
- [RVM-63] - Unsafe.park time values are incorrectly scaled
- [RVM-87] - NPE in ScanThread.setUpFrame:360
- [RVM-99] - MeasureCompilation reporting broken in production/development builds on ia32-linux
- [RVM-104] - eclipse occasionally fails with segmentation fault
- [RVM-109] - Restore documentation to org.vmmagic.pragma.*
- [RVM-112] - Verification error when building Jikes RVM 2.9.1 using HotSpot as host JVM.
- [RVM-113] - MarkCompactLocal.compact():80 assertion failure
- [RVM-114] - Ensure time is positive in test results
- [RVM-125] - Waiting on a lock that should raise illegal monitor state exception will actual fail on an assert
- [RVM-129] - GCTrace fails with "Cannot understand directive!"
- [RVM-131] - Collection.joinCollection() called when thread switching disabled
- [RVM-133] - Increase the amount of memory used during nightly tests
- [RVM-140] - Conflicting virtual address request for space "trace" on ppc32-linux
- [RVM-141] - SharedDeque assertion failure during exit for GCTrace
- [RVM-143] - VM_BuildBB.determineTheBasicBlock may not be correct for goto_w operation
- [RVM-144] - JikesRVM can't load certain classes e.g. GNU Classpath examples or its own Ant tasks
- [RVM-150] - Unexpectedly large processor lock contention
- [RVM-154] - A shutdown hook can hang RVM
- [RVM-155] - SynchronizationBarrier.removeProcessor assertion failure
- [RVM-159] - OSR-guarded inlining should not be allowed in uninterruptible code
- [RVM-181] - ClassCastException in OPT_Simplifier when running antlr DaCapo
- [RVM-183] - Thread sitting on >1 queue
- [RVM-194] - Assertion failure in OSR State Extractor running chart
- [RVM-198] - NPE when unlocking lock
- [RVM-201] - Classpath AWT is broken
- [RVM-203] - terminal not in grammar: new
- [RVM-204] - Reduce wasted code space on inline allocation path
- [RVM-206] - Stack walking in MMTk not correctly identifying not yet obsolete methods?
- [RVM-209] - Bootimage bloat broke ppc64-aix images
- [RVM-213] - jbb2005 performance regression
- [RVM-216] - MMTk assertion failure during jbb large heap performance runs
- [RVM-219] - Address.attempt*() compiles incorrectly on IA32 with Jikes 2.9.1
- [RVM-220] - jbb2005 GC performance mode: Warning: number of GC phases exceeds MAX_PHASES
- [RVM-242] - Build break: BaseBaseGCTrace
- [RVM-245] - Change to deques appears to have significantly reduced hsqldb performance
- [RVM-270] - NPEs from barrier code not working
- [RVM-277] - lusearch fails on PPC32 due to validation error
- [RVM-279] - Performance regression
- [RVM-293] - Class loaders do not isolate packages with the same name
- [RVM-297] - Classpath 0.96 configure problems with JDK 1.6
- [RVM-298] - DaCapo chart broken on classpath 0.96
- [RVM-299] - possible performance regression on xalan on classpath 0.96
- [RVM-301] - JSR 166 failures
Tasks and Sub-tasks
- [RVM-38] - VM_BaselineBootImageCompiler should use System.nanoTime rather than DNA for compilation time
- [RVM-286] - _201_compress took a 10% hit when we switched to Arnold/Grove call graph profiling; investigate
- [RVM-217] - Recode spin loop in org.mmtk.utility.deque.Deque spinWait to reduce frequency of nanoTime calls
- [RVM-230] - Determine whether patching Classpath sources is preferable to bytecode engineering adding annotations