Beyond JVM

Talk on interesting JVM-related upcoming technologies as delivered at YOW! Melbourne 2013.

Transcript

1. Beyond JVM A tour of upcoming technologies
2. Reminders • Green/yellow/red rating system after talk • Extended Q/A by blue chairs at 12:15 • If not green…stop by and tell me why
3. Me • Charles Oliver Nutter • Red Hat (yes, I have one; no, I don’t wear it) • JRuby and JVM languages • JVM hacking and spelunking • @headius
4. Goals • Get you excited about the future of JVM • Show you there are very few unsolvables • Convince you to get involved
5. What is “JVM”? • The JVM is software that runs JVM bytecode • Java, Scala, Groovy, JRuby, Clojure, … • OpenJDK contains Sun’s JVM “HotSpot” • Oracle’s JDK is based on OpenJDK • Many other JVMs exist for many platforms • Some just replace HotSpot
6. OSS JVMs • Avian • Azul Zulu • CACAO • Dalvik • GCJ • HaikuVM • HotSpot • IcedTea • IKVM.NET • Jamiga • JamVM • Jaos • Jato VM • Jelatine JVM • JESSICA • Jikes RVM (Jikes Research Virtual Machine) • JOP • Juice • Jupiter • JwiK • Kaffe • leDos • MateVM • Maxine • Mika VM • miniMV • Mysaifu • NanoVM • RoboVM • SableVM • Squawk virtual machine • SuperWaba • TakaTuka • TinyVM. • VM02
7. Why JVM?
8. Why Not JVM?
12. OpenJDK
13. OpenJDK Timeline • For years, Sun’s JDK is closed source • Sun Microsystems starts OSS process in 2005 • Official announcement at JavaOne 2006 • HotSpot OSSed 12 Nov 2006 • JDK OSSed 8 May 2007
14. A 2006 report prepared for the EU by UNU-MERIT stated that Sun was the largest corporate contributor to open source movements in the world.
15. According to this report, Sun's open source contributions exceed the combined total of the next five largest commercial contributors.
16. Unfortunately…
17. Sun Becomes Oracle • Sun broke open the OSS piñata • Java, Solaris, OpenOffice, NetBeans, VirtualBox, ZFS, Dtrace, and more • Unable to capitalize on OSS • Hardware can’t make up the difference • Oracle takes over Sun…oh no!!!
23. Java SE 7 Updates 0 22.5 45 67.5 90 7u1 7u2 7u3 7u4 7u5 7u6 7u7 7u9 7u10 7u11 7u13 7u15 7u17 7u21 7u25 7u40 7u45 Time since last release Flurry of exploits New numbering 9mo of security releases
24. The OpenJDK landscape looks different this year. Oracle's complete grip on OpenJDK is slowly loosening. They're still the dominant player and perhaps always will be, but things are more level than they were.! ! - Andrew Haley of Red Hat! ! Upon nomination to the OpenJDK governing board for 2013
25. Truths of OpenJDK • It is really truly OSS, under GPL+CPE • You can fork it • You can distribute builds of it • You can contribute to it • Oracle is learning how to do OSS
27. Java 5 was released September 30, 2004
28. Java 6 was released December 11, 2006
29. Java 7 was released July 28, 2011
30. Java 7 Features • Strings in switch statements • More numeric literal forms • Type inference for generic instances • try-with-resources statement • Multiple-catch
31. static String chooseGreeting(String language) {" switch (language) {" case "Java": return "I love to hate you!";" case "Scala": return "I love you, I think!";" case "Clojure": return "(love I you)";" case "Groovy": return "I love ?: you";" case "Ruby": return "I.love? you # => true";" default: return "Who are you?";" }" }
32. Java 8 Features • Lambda expressions • Type annotations
33. Java 8 Features • Lambda expressions • Type annotations
34. public static void doSort(List<String> input) {" Collections.sort(input,! (a,b)->Integer.compare(a.length(), b.length()));" }" " public static String getInitials(List<String> input) {" return input.stream()" .map(x->x.substring(0,1))" .collect(Collectors.joining());" }
35. Java 9 Features? • Modularization? • Dynamic invocation? • Value types? • Reified generics? • Coroutines? (working patch available!) • Tail calls? (working patch available!)
36. Alternative Languages
37. High-Profile Languages • Clojure • Groovy • Scala • JRuby
38. Newcomers • Kotlin • Ceylon • Xtend • Mirah
39. Classics • Jython • Rhino • BeanShell
40. Ported Languages • Ada • AWK • BASIC • BBx • Boo • C • COBOL • ColdFusion • Railo • Open BlueDragon • Common Lisp • Component Pascal • Erlang • Forth • Go • Haxe • JavaScript • Logo • Lua • Yeti ML • Oberon-2 • OCaml • Object Pascal • PHP • Prolog • Python • R • REXX • Ruby • Scheme • Smalltalk • Tcl
41. New Languages • Alef++ • Ateji PX • BBj • BeanShell • Ceylon • CAL • E • Fantom • Flow Java. • Fortress • Frege • Frink • Golo • Gosu • Hecl • Ioke • KBML • Kotlin • Jabaco • Jaskell • Jelly • Join Java • Joy • Judoscript • Libretto. • Mirah • N.A.M.E. Basic. • NetLogo • Nice • Noop • ObjectScript • PHP.reboot • Pizza • Pnuts • Processing • Stab • Sleep • V • X10 • Xtend • Zest
42. JVM is not just Java
44. Native Interop
47. User Code JNI call JNI impl Target Library Java C/native
48. public class GetPidJNI {" public static native long getpid();" " public static void main( String[] args ) {" getpid();" }" " static {" System.load(! System.getProperty("user.dir") +! "/getpidjni.dylib");" }" } JNI
49. /* DO NOT EDIT THIS FILE - it is machine generated */" #include <jni.h>" /* Header for class com_headius_jnr_presentation_GetPidJNI */" " #ifndef _Included_com_headius_jnr_presentation_GetPidJNI" #define _Included_com_headius_jnr_presentation_GetPidJNI" #ifdef __cplusplus" extern "C" {" #endif" /*" * Class: com_headius_jnr_presentation_GetPidJNI" * Method: getpid" * Signature: ()J" */" JNIEXPORT jlong JNICALL Java_com_headius_jnr_1presentation_GetPidJNI_getpid" (JNIEnv *, jclass);" " #ifdef __cplusplus" }" #endif" #endif JNI
50. #include "com_headius_jnr_presentation_GetPidJNI.h"" " jlong JNICALL Java_com_headius_jnr_1presentation_GetPidJNI_getpid" (JNIEnv *env, jclass c) {" " return getpid();" } JNI
51. $ gcc -I $JAVA_HOME/include -I $JAVA_HOME/include/darwin -L $JAVA_HOME/jre/lib/ -dynamiclib -ljava -o getpidjni.dylib com_headius_jnr_presentation_GetPidJNI. c" ! $ java -Djava.library.path=`pwd` -cp target/jnr_presentation-1.0- SNAPSHOT.jar com.headius.jnr_presentation.GetPidJNI JNI
52. Nobody enjoys calling native libraries...
53. ...but if you have to call native libraries, you might as well enjoy it.
54. Java Native Runtime • Java API • for calling Native code • supported by a rich Runtime library • You may be familiar with JNA • Foreign Function Interface (FFI) • https://github.com/jnr • Maven artifacts for everything
55. A Java API for binding native libraries and native memory
56. Justifications • NIO, NIO.2 • Native IO, symlinks, FS-walking, • Unmanaged memory • Selectable stdio, process IO • Low-level or other sockets (UNIX, ICMP, ...) • New APIs (graphics, crypto, OS, ...)
57. User Code JNI call JNI impl Target Library Java C/native
58. User Code JNI call JNI impl Target Library Java C/native
59. User Code JNR stub JNI call JNI impl libffi Target Library Java C/native
60. import jnr.ffi.LibraryLoader;" import jnr.ffi.annotations.IgnoreError;" " public class GetPidJNRExample {" public interface GetPid {" long getpid();" }" " public static void main( String[] args ) {" GetPid getpid = LibraryLoader" .create(GetPid.class)! .load("c");" " getpid.getpid();" }" } JNR
61. Layered Runtime jffi jnr-ffi libffi jnr-posix jnr-constants ! jnr-enxio jnr-x86asm jnr-unixsocket etc etc
62. JNR Platforms • Darwin (OS X): universal (+ppc?) • Linux: i386, x86_64, arm, ppc, ppc64, s390x • Windows: i386, x86_64 • FreeBSD, OpenBSD: i386, x86_64 • SunOS: i386, x86_64, sparc, sparcv9 • AIX: ppc • OpenVMS, AS/400: builds out there somewhere • If your platform isn't here, contribute a build
63. jnr-ffi • User-oriented API • Roughly equivalent to what JNA gives you • Functions, structs, callbacks, memory • https://github.com/jnr/jnr-ffi
64. import jnr.ffi.LibraryLoader;" import jnr.ffi.annotations.IgnoreError;" " public class GetPidJNRExample {" public interface GetPid {" long getpid();" }" " public static void main( String[] args ) {" GetPid getpid = LibraryLoader" .create(GetPid.class)! .load("c");" " getpid.getpid();" }" } jnr-ffi
65. jnr-posix • Pre-bound set of POSIX functions • Mostly driven by what JRuby, Jython use • Goal: 100% of POSIX bound to Java
66. public int chmod(String string, int i);" public int chown(String string, int i, int i1);" public int execv(String string, String[] strings);" public int execve(String string, String[] strings, String[] strings1);" public int fork();" public int seteuid(int i);" public int getgid();" public String getlogin();" public int getpgid();" public int getpgid(int i);" public int getpgrp();" public int getpid();" public int getppid();" public Passwd getpwent();! public Passwd getpwuid(int i);! public Passwd getpwnam(String string);" public Group getgrgid(int i);! public Group getgrnam(String string);" public int getuid();! public boolean isatty(FileDescriptor fd);" public int kill(int i, int i1);! public int symlink(String string, String string1);" public int link(String string, String string1);" public String readlink(String string) throws IOException;" public String getenv(String string);" public int setenv(String string, String string1, int i);" public int unsetenv(String string);" public int getpriority(int i, int i1);" public int setpriority(int i, int i1, int i2);" public int setuid(int i);" public FileStat stat(String string);" public int stat(String string, FileStat fs);" public int umask(int i);" public Times times();" public int utimes(String string, long[] longs, long[] longs1);" public int waitpid(int i, int[] ints, int i1);" public int wait(int[] ints);" public int errno();" public void errno(int i);" public int posix_spawnp(String string, List<? extends SpawnFileAction> list, List<? extends CharSequence> list1, List<? extends CharSequence> list2);
67. POSIX posix = POSIXFactory.getPOSIX(! new MyPOSIXHandler(this)," isNativeEnabled);
68. public interface POSIXHandler {! public void error(Errno errno, String string);" public void unimplementedError(String string);! public void warn(WARNING_ID wrngd, String string, Object[] os);" public boolean isVerbose();! public File getCurrentWorkingDirectory();! public String[] getEnv();! public InputStream getInputStream();! public PrintStream getOutputStream();! public int getPID();! public PrintStream getErrorStream();" }
69. jnr-enxio • Extended Native X-platform IO • NIO-compatible JNR-backed IO library • Read, write, select (kqueue, epoll, etc) • Low-level fcntl control • https://github.com/jnr/jnr-enxio
70. public class NativeSocketChannel" extends AbstractSelectableChannel" implements ByteChannel, NativeSelectableChannel {" public NativeSocketChannel(int fd);! public NativeSocketChannel(int fd, int ops);! public final int validOps();! public final int getFD();! public int read(ByteBuffer dst) throws IOException;" public int write(ByteBuffer src) throws IOException" public void shutdownInput() throws IOException;" public void shutdownOutput() throws IOException;! }
71. jnr-unixsocket • UNIX sockets for NIO • Built atop jnr-enxio • Fully selectable, etc • https://github.com/jnr/jnr-unixsocket
72. How Does It Perform?
73. getpid calls, 100M times 1ms 10ms 100ms 1000ms 10000ms 100000ms JNA getpid JNR getpid
74. import jnr.ffi.LibraryLoader;" import jnr.ffi.annotations.IgnoreError;" " public class GetPidJNRExample {" public interface GetPid {" @IgnoreError" long getpid();" }" " public static void main( String[] args ) {" GetPid getpid = LibraryLoader" .create(GetPid.class)! .load("c");" " getpid.getpid();" }" } @IgnoreError
75. getpid calls, 100M times 0ms 500ms 1000ms 1500ms 2000ms JNR getpid JNR getpid @IgnoreError
76. getpid calls, 100M times 0ms 500ms 1000ms 1500ms 2000ms JNR getpid JNI JNR @IgnoreError GCC -O3 But There's More to Do
77. JVM Help is Coming • Standard FFI API in JDK • JIT intelligence • Drop JNI overhead where possible • Bind native call directly at call site • Security policies, segv protection, etc • Time for an FFI JSR
78. Recap • OpenJDK is awesome • Java is evolving • JVM languages are everywhere • Even native code is accessible
79. 27 April, 2011
80. History • JVM authors mentioned non-Java languages • Language authors have targeted JVM • Hundreds of JVM languages now • But JVM was a mismatch for many of them • Usually required tricks that defeated JVM optimizations • Or required features JDK could not provide
81. What is invokedynamic
82. JVM Opcodes Invocation invokevirtual" invokeinterface" invokestatic" invokespecial Field Access getfield" setfield" getstatic" setstatic Array Access *aload" *astore" b,s,c,i,l,d,f,a Stack Local Vars Flow Control Allocation Boolean and Numeric
84. Goals of JSR 292 • A user-definable bytecode • Full freedom to define VM behavior • Fast method pointers + adapters • Optimizable like normal Java code • Avoid future modifications
85. +
    Method Pointers
    and Adapters Faster than reflection, with user-defined argument, flow, and exception handling A User-definable Bytecode You decide how the JVM implements it
86. invokedynamic user-def’d bytecode invokedynamic opcode method pointers MethodHandles
87. VM Operations Method Lookup Type Checking Branch Method Cache Method Invocation Target Object Object’s Class void foo() static void bar() instanceof obj.foo() JVM void foo() Call Site
88. // Static" System.currentTimeMillis()" Math.log(1.0)" " // Virtual" "hello".toUpperCase()" System.out.println()" " // Interface" myList.add("happy happy")" myRunnable.run()" " // Special" new ArrayList()" super.equals(other)
89. // Static" invokestatic java/lang/System.currentTimeMillis:()J" invokestatic java/lang/Math.log:(D)D" ! // Virtual" invokevirtual java/lang/String.toUpperCase:()Ljava/lang/String;" invokevirtual java/io/PrintStream.println:()V" ! // Interface" invokeinterface java/util/List.add:(Ljava/lang/Object;)Z" invokeinterface java/lang/Runnable.add:()V" ! // Special" invokespecial java/util/ArrayList.<init>:()V" invokespecial java/lang/Object.equals:(java/lang/Object)Z invokestatic invokevirtual invokeinterface invokespecial
90. invokestatic" 1. Confirm arguments are of correct type 2. Look up method on Java class 3. Cache method 4. Invoke method invokevirtual" 1. Confirm object is of correct type 2. Confirm arguments are of correct type 3. Look up method on Java class 4. Cache method 5. Invoke method invokeinterface" 1. Confirm object’s type implements interface 2. Confirm arguments are of correct type 3. Look up method on Java class 4. Cache method 5. Invoke method invokespecial" 1. Confirm object is of correct type 2. Confirm arguments are of correct type 3. Confirm target method is visible 4. Look up method on Java class 5. Cache method 6. Invoke method invokestatic invokevirtual invokeinterface invokespecial invokedynamic! 1. Call bootstrap handle (your code) 2. Bootstrap prepares CallSite + MethodHandle 3. MethodHandle invoked now and future (until CallSite changes)
91. method handles invokedynamic bytecode bootstrap m ethod target method
92. How Do You Benefit?
93. Indy Languages • New language impls • JavaScript: Dyn.js and Nashorn • Redline Smalltalk • Improved language performance • JRuby, Groovy, Jython • Java features too!
94. Times Faster than Ruby 1.9.3 0 1.25 2.5 3.75 5 base64 richards neural redblack 4.32 3.66 3.44 2.658 1.565 1.914 1.538 1.346 JRuby/Java 6 JRuby/Java 7
95. red/black tree, pure Ruby versus native ruby-2.0.0 + Ruby ruby-2.0.0 + C ext jruby + Ruby Runtime per iteration 0 0.75 1.5 2.25 3 0.29s 0.51s 2.48s
96. Caveat Emptor • Indy was really slow in first Java 7 release • Got fast in 7u2...and turned out broken • Rewritten for 7u40 • Slow to warm up • Still some issues (memory use, etc) • Java 8 due in March…
97. Feeling Helpless?
98. Out of our control Written in C++ JVM Bytecode JVM Language Bytecode Interpreter Bytecode JIT Native Code
99. What If… • The JVM’s JIT optimizer were written in Java • You could customize how the JIT works for your language or library • JITed code could directly make native calls
100. Graal • A 100% Java-based JIT framework • Grew out of the 100% Java “Maxine” JVM • Backends to assembly or HotSpot IR • Directly control code generation • Build a language without using JVM bytecode • http://openjdk.java.net/projects/graal/
101. Graal Intermediate Representation JVM Language Graal Optimizer Native Code Your Transformations Your Optimizations Plain Java APIs Under your control
102. However… • Not everyone is a compiler writer • Graal’s IR is low-level and nontrivial • Need to understand JVM internals • Need some understanding of CPU
103. The Dream • Design your language • ??? • PROFIT
104. Without JVM • Design your language • Work out memory model • Create an optimizing compiler • Spend ten years debugging it • PROFIT
105. With JVM • Design your language • Maybe write an interpreter • Compile to JVM bytecode • Pray that the JVM optimizes it right • PROFIT
106. What We Want • Design your language • ??? • PROFIT
107. What We Want • Design your language • Write an interpreter • PROFIT
108. Truffle • Language framework built on Graal • Designed to fulfill the dream • Implement interpreter • Truffle feeds that to backend • No compiler expertise needed • https://wiki.openjdk.java.net/display/Graal/Truffle+FAQ+and+Guidelines
109. Traditional Approach Any JVM Custom made bytecode compiler Guest Language AST interpreter in pure Java Bytecode emitted by guest language
110. Truffle Atop JVM Any JVM Truffle Guest Language AST interpreter in pure Java Bytecode based on interpreter flow
111. Truffle Atop Graal Graal JVM Truffle Guest Language AST interpreter in pure Java Direct access to compiler internals, IR, machine code cache, on stack replacement, etc etc
114. The Final Word • JVM is a powerful platform • Java and other languages are evolving • The JVM is adapting to our needs • New tools breaking JVM’s boundaries
115. Thank you! • Charles Oliver Nutter • @headius, headius@headius.com • http://blog.headius.com