Beyond JVM
A tour of upcoming technologies
Reminders
• Green/yellow/red rating system after talk	

• Extended Q/A by blue chairs at 12:15	

• If not green…stop by an...
Me
• Charles Oliver Nutter	

• Red Hat (yes, I have one; no, I don’t wear it)	

• JRuby and JVM languages	

• JVM hacking ...
Goals
• Get you excited about the future of JVM	

• Show you there are very few unsolvables	

• Convince you to get involv...
What is “JVM”?
• The JVM is software that runs JVM bytecode	

• Java, Scala, Groovy, JRuby, Clojure, …	

• OpenJDK contain...
OSS JVMs
•
•
•
•
•
•
•
•
•

Avian	

Azul Zulu	

CACAO	

Dalvik	

GCJ	

HaikuVM	

HotSpot	


•
•
•
•
•
•
•

IcedTea	

IKVM....
Why JVM?
Why Not JVM?
OpenJDK
OpenJDK Timeline
• For years, Sun’s JDK is closed source	

• Sun Microsystems starts OSS process in 2005	

• Official annou...
A 2006 report prepared for the EU
by UNU-MERIT stated that Sun was
the largest corporate contributor to
open source moveme...
According to this report, Sun's open
source contributions exceed the
combined total of the next five
largest commercial con...
Unfortunately…
Sun Becomes Oracle
• Sun broke open the OSS piñata	

• Java, Solaris, OpenOffice, NetBeans,
VirtualBox, ZFS, Dtrace, and mo...
Java SE 7 Updates
Time since last release

New numbering
90

Flurry of exploits
67.5

45

22.5

9mo of security releases
0...
The OpenJDK landscape looks different
this year. Oracle's complete grip on
OpenJDK is slowly loosening. They're
still the ...
Truths of OpenJDK
• It is really truly OSS, under GPL+CPE	

• You can fork it	

• You can distribute builds of it	

• You ...
Java 5 was released	

September 30, 2004
Java 6 was released	

December 11, 2006
Java 7 was released	

July 28, 2011
Java 7 Features
• Strings in switch statements	

• More numeric literal forms	

• Type inference for generic instances	

•...
    static String chooseGreeting(String language) {"
        switch (language) {"
            case "Java": return "I love ...
Java 8 Features
• Lambda expressions	

• Type annotations
Java 8 Features

•

Lambda expressions	


• Type annotations
public static void doSort(List<String> input) {"
Collections.sort(input,!
(a,b)->Integer.compare(a.length(), b.length()));...
Java 9 Features?
• Modularization?	

• Dynamic invocation?	

• Value types?	

• Reified generics?	

• Coroutines? (working ...
Alternative Languages
High-Profile Languages
• Clojure	

• Groovy	

• Scala	

• JRuby
Newcomers
• Kotlin	

• Ceylon	

• Xtend	

• Mirah
Classics
• Jython	

• Rhino	

• BeanShell
Ported Languages
•
•
•
•
•
•
•
•
•

Ada	

AWK	

BASIC	

BBx	

Boo	

C	

COBOL	

ColdFusion	

Railo	


•

Open
BlueDragon	
...
New Languages
•
•
•
•
•
•
•
•
•
•
•

Alef++	

Ateji PX	

BBj	

BeanShell	

Ceylon	

CAL	

E	

Fantom	

Flow Java.	

Fortre...
JVM is not just Java
Native Interop
User Code

Java

JNI call

C/native

JNI impl
Target Library
JNI
public class GetPidJNI {"
public static native long getpid();"
"
public static void main( String[] args ) {"
getpid();...
JNI
/* DO NOT EDIT THIS FILE - it is machine generated */"
#include <jni.h>"
/* Header for class com_headius_jnr_presentat...
JNI
#include "com_headius_jnr_presentation_GetPidJNI.h""
 "
jlong JNICALL Java_com_headius_jnr_1presentation_GetPidJNI_get...
JNI
$ gcc -I $JAVA_HOME/include -I
$JAVA_HOME/include/darwin -L
$JAVA_HOME/jre/lib/ -dynamiclib -ljava
-o getpidjni.dylib
...
Nobody enjoys calling
native libraries...
...but if you have to call
native libraries, you
might as well enjoy it.
Java Native Runtime
• Java API	

• for calling Native code	

• supported by a rich Runtime library	

• You may be familiar...
A Java API for binding
native libraries and
native memory
Justifications
• NIO, NIO.2	

• Native IO, symlinks, FS-walking, 	

• Unmanaged memory	

• Selectable stdio, process IO	

•...
User Code

Java

JNI call

C/native

JNI impl
Target Library
User Code

Java

JNI call

C/native

JNI impl
Target Library
User Code
JNR stub

Java

JNI call

C/native

JNI impl
libffi
Target Library
JNR
import jnr.ffi.LibraryLoader;"
import jnr.ffi.annotations.IgnoreError;"
 "
public class GetPidJNRExample {"
public int...
Layered Runtime
etc etc
jnr-posix	


jnr-unixsocket!
jnr-enxio

jnr-constants

jnr-ffi
jffi
libffi

jnr-x86asm
JNR Platforms
• Darwin (OS X): universal (+ppc?)	

• Linux: i386, x86_64, arm, ppc, ppc64, s390x	

• Windows: i386, x86_64...
jnr-ffi
• User-oriented API	

• Roughly equivalent to what JNA gives you	

• Functions, structs, callbacks, memory	

• http...
jnr-ffi
import jnr.ffi.LibraryLoader;"
import jnr.ffi.annotations.IgnoreError;"
 "
public class GetPidJNRExample {"
public ...
jnr-posix
• Pre-bound set of POSIX functions	

• Mostly driven by what JRuby, Jython use	

• Goal: 100% of POSIX bound to ...
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
public
pub...
POSIX posix = POSIXFactory.getPOSIX(!
new MyPOSIXHandler(this),"
isNativeEnabled);
public interface POSIXHandler {!
public void error(Errno errno, String string);"
public void unimplementedError(String str...
jnr-enxio
• Extended Native X-platform IO	

• NIO-compatible JNR-backed IO library	

• Read, write, select (kqueue, epoll,...
public class NativeSocketChannel"
extends AbstractSelectableChannel"
implements ByteChannel, NativeSelectableChannel {"
pu...
jnr-unixsocket
• UNIX sockets for NIO	

• Built atop jnr-enxio	

• Fully selectable, etc	

• https://github.com/jnr/jnr-un...
How Does It Perform?
JNA getpid

JNR getpid

getpid calls, 100M times
100000ms
10000ms
1000ms
100ms
10ms
1ms
@IgnoreError
import jnr.ffi.LibraryLoader;"
import jnr.ffi.annotations.IgnoreError;"
 "
public class GetPidJNRExample {"
p...
JNR getpid

JNR getpid @IgnoreError
getpid calls, 100M times

2000ms

1500ms

1000ms

500ms

0ms
But There's More to Do
JNR getpid

JNI

JNR @IgnoreError
getpid calls, 100M times

2000ms
1500ms
1000ms
500ms
0ms

GCC -O3
JVM Help is Coming
• Standard FFI API in JDK	

• JIT intelligence	

• Drop JNI overhead where possible	

• Bind native cal...
Recap
• OpenJDK is awesome	

• Java is evolving	

• JVM languages are everywhere	

• Even native code is accessible
27 April, 2011
History
• JVM authors mentioned non-Java languages	

• Language authors have targeted JVM	

• Hundreds of JVM languages no...
What is
invokedynamic
JVM
Opcodes
Invocation	


Field Access	


invokevirtual"
invokeinterface"
invokestatic"
invokespecial

getfield"
setfield"...
Goals of JSR 292
• A user-definable bytecode	

• Full freedom to define VM behavior	

• Fast method pointers + adapters	

• ...
A User-definable
Bytecode
You decide how the JVM implements it

+
Method Pointers
and Adapters
Faster than reflection, with ...
invokedynamic opcode
user-def’d bytecode

method pointers
MethodHandles

invokedynamic
Method Invocation
VM Operations	

Method Lookup	

Type Checking	

Branch	

Method Cache

obj.foo()

Target	

Object
JVM

C...
// Static"
System.currentTimeMillis()"
Math.log(1.0)"
 "
// Virtual"
"hello".toUpperCase()"
System.out.println()"
 "
// In...
// Static"
invokestatic java/lang/System.currentTimeMillis:()J"
invokestatic java/lang/Math.log:(D)D"
!
// Virtual"
invoke...
invokevirtual"
1. Confirm object is of correct type	

2. Confirm arguments are of correct type	

3. Look up method on Java c...
invokedynamic bytecode
target method

bo
ot
st

ra
p

m

et
ho
d

method handles
How Do You Benefit?
Indy Languages
• New language impls	

• JavaScript: Dyn.js and Nashorn	

• Redline Smalltalk	

• Improved language perform...
JRuby/Java 6

JRuby/Java 7

Times Faster than Ruby 1.9.3
5
4.32

3.75

3.66
3.44

2.5

2.658

1.914

1.25

0

1.346

base6...
red/black tree, pure Ruby versus native

ruby-2.0.0 + Ruby

2.48s

ruby-2.0.0 + C ext

0.51s

jruby + Ruby

0.29s

0

0.75...
Caveat Emptor
• Indy was really slow in first Java 7 release	

• Got fast in 7u2...and turned out broken	

• Rewritten for ...
Feeling Helpless?
JVM
Language

JVM
Bytecode

Out of our control	

Written in C++

Bytecode
Interpreter

Bytecode
JIT

Native
Code
What If…
• The JVM’s JIT optimizer were written in Java	

• You could customize how the JIT works for
your language or lib...
Graal
• A 100% Java-based JIT framework	

• Grew out of the 100% Java “Maxine” JVM	

• Backends to assembly or HotSpot IR	...
JVM
Language
Plain Java APIs

Graal	

Intermediate
Representation

Graal
Optimizer

Under your control

Your
Transformatio...
However…
• Not everyone is a compiler writer	

• Graal’s IR is low-level and nontrivial	

• Need to understand JVM interna...
The Dream
• Design your language	

• ???	

• PROFIT
Without JVM
• Design your language	

• Work out memory model	

• Create an optimizing compiler	

• Spend ten years debuggi...
With JVM
• Design your language	

• Maybe write an interpreter	

• Compile to JVM bytecode	

• Pray that the JVM optimizes...
What We Want
• Design your language	

• ???	

• PROFIT
What We Want
• Design your language	

• Write an interpreter	

• PROFIT
Truffle
• Language framework built on Graal	

• Designed to fulfill the dream	

• Implement interpreter	

• Truffle feeds tha...
Traditional Approach
Guest Language
AST interpreter in pure Java

Custom made bytecode compiler
Bytecode emitted by guest ...
Truffle Atop JVM
Guest Language
AST interpreter in pure Java

Truffle
Bytecode based on interpreter flow

Any JVM
Truffle Atop Graal
Guest Language
AST interpreter in pure Java

Truffle
Direct access to compiler internals,	

IR, machine c...
The Final Word
• JVM is a powerful platform	

• Java and other languages are evolving	

• The JVM is adapting to our needs...
Thank you!
• Charles Oliver Nutter	

• @headius, headius@headius.com	

• http://blog.headius.com
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
Beyond JVM - YOW Melbourne 2013
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Beyond JVM - YOW Melbourne 2013

  1. 1. Beyond JVM A tour of upcoming technologies
  2. 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. 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. 4. Goals • Get you excited about the future of JVM • Show you there are very few unsolvables • Convince you to get involved
  5. 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. 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 • • • • SuperWaba NanoVM RoboVM SableVM Squawk virtual machine TakaTuka TinyVM. VM02
  7. 7. Why JVM?
  8. 8. Why Not JVM?
  9. 9. OpenJDK
  10. 10. 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
  11. 11. 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.
  12. 12. According to this report, Sun's open source contributions exceed the combined total of the next five largest commercial contributors.
  13. 13. Unfortunately…
  14. 14. 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!!!
  15. 15. Java SE 7 Updates Time since last release New numbering 90 Flurry of exploits 67.5 45 22.5 9mo of security releases 0 45 7u 40 7u 25 7u 21 7u 17 7u 15 7u 13 7u 11 7u 10 7u 9 7u 7 7u 6 7u 5 7u 4 7u 3 7u 2 7u 1 7u
  16. 16. 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
  17. 17. 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
  18. 18. Java 5 was released September 30, 2004
  19. 19. Java 6 was released December 11, 2006
  20. 20. Java 7 was released July 28, 2011
  21. 21. Java 7 Features • Strings in switch statements • More numeric literal forms • Type inference for generic instances • try-with-resources statement • Multiple-catch
  22. 22.     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?";"         }"     }
  23. 23. Java 8 Features • Lambda expressions • Type annotations
  24. 24. Java 8 Features • Lambda expressions • Type annotations
  25. 25. 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());" }
  26. 26. Java 9 Features? • Modularization? • Dynamic invocation? • Value types? • Reified generics? • Coroutines? (working patch available!) • Tail calls? (working patch available!)
  27. 27. Alternative Languages
  28. 28. High-Profile Languages • Clojure • Groovy • Scala • JRuby
  29. 29. Newcomers • Kotlin • Ceylon • Xtend • Mirah
  30. 30. Classics • Jython • Rhino • BeanShell
  31. 31. 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
  32. 32. 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
  33. 33. JVM is not just Java
  34. 34. Native Interop
  35. 35. User Code Java JNI call C/native JNI impl Target Library
  36. 36. JNI public class GetPidJNI {" public static native long getpid();" " public static void main( String[] args ) {" getpid();" }" " static {" System.load(! System.getProperty("user.dir") +! "/getpidjni.dylib");" }" }
  37. 37. JNI /* 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
  38. 38. JNI #include "com_headius_jnr_presentation_GetPidJNI.h""  " jlong JNICALL Java_com_headius_jnr_1presentation_GetPidJNI_getpid" (JNIEnv *env, jclass c) {"  " return getpid();" }
  39. 39. JNI $ 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-1.0SNAPSHOT.jar com.headius.jnr_presentation.GetPidJNI
  40. 40. Nobody enjoys calling native libraries...
  41. 41. ...but if you have to call native libraries, you might as well enjoy it.
  42. 42. 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
  43. 43. A Java API for binding native libraries and native memory
  44. 44. 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, ...)
  45. 45. User Code Java JNI call C/native JNI impl Target Library
  46. 46. User Code Java JNI call C/native JNI impl Target Library
  47. 47. User Code JNR stub Java JNI call C/native JNI impl libffi Target Library
  48. 48. JNR 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();" }" }
  49. 49. Layered Runtime etc etc jnr-posix jnr-unixsocket! jnr-enxio jnr-constants jnr-ffi jffi libffi jnr-x86asm
  50. 50. 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
  51. 51. jnr-ffi • User-oriented API • Roughly equivalent to what JNA gives you • Functions, structs, callbacks, memory • https://github.com/jnr/jnr-ffi
  52. 52. jnr-ffi 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();" }" }
  53. 53. jnr-posix • Pre-bound set of POSIX functions • Mostly driven by what JRuby, Jython use • Goal: 100% of POSIX bound to Java
  54. 54. public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public public List<? int chmod(String string, int i);" int chown(String string, int i, int i1);" int execv(String string, String[] strings);" int execve(String string, String[] strings, String[] strings1);" int fork();" int seteuid(int i);" int getgid();" String getlogin();" int getpgid();" int getpgid(int i);" int getpgrp();" int getpid();" int getppid();" Passwd getpwent();! Passwd getpwuid(int i);! Passwd getpwnam(String string);" Group getgrgid(int i);! Group getgrnam(String string);" int getuid();! boolean isatty(FileDescriptor fd);" int kill(int i, int i1);! int symlink(String string, String string1);" int link(String string, String string1);" String readlink(String string) throws IOException;" String getenv(String string);" int setenv(String string, String string1, int i);" int unsetenv(String string);" int getpriority(int i, int i1);" int setpriority(int i, int i1, int i2);" int setuid(int i);" FileStat stat(String string);" int stat(String string, FileStat fs);" int umask(int i);" Times times();" int utimes(String string, long[] longs, long[] longs1);" int waitpid(int i, int[] ints, int i1);" int wait(int[] ints);" int errno();" void errno(int i);" int posix_spawnp(String string, List<? extends SpawnFileAction> list, extends CharSequence> list1, List<? extends CharSequence> list2);
  55. 55. POSIX posix = POSIXFactory.getPOSIX(! new MyPOSIXHandler(this)," isNativeEnabled);
  56. 56. 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();" }
  57. 57. 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
  58. 58. 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;! }
  59. 59. jnr-unixsocket • UNIX sockets for NIO • Built atop jnr-enxio • Fully selectable, etc • https://github.com/jnr/jnr-unixsocket
  60. 60. How Does It Perform?
  61. 61. JNA getpid JNR getpid getpid calls, 100M times 100000ms 10000ms 1000ms 100ms 10ms 1ms
  62. 62. @IgnoreError 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();" }" }
  63. 63. JNR getpid JNR getpid @IgnoreError getpid calls, 100M times 2000ms 1500ms 1000ms 500ms 0ms
  64. 64. But There's More to Do JNR getpid JNI JNR @IgnoreError getpid calls, 100M times 2000ms 1500ms 1000ms 500ms 0ms GCC -O3
  65. 65. 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
  66. 66. Recap • OpenJDK is awesome • Java is evolving • JVM languages are everywhere • Even native code is accessible
  67. 67. 27 April, 2011
  68. 68. 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
  69. 69. What is invokedynamic
  70. 70. JVM Opcodes Invocation Field Access invokevirtual" invokeinterface" invokestatic" invokespecial getfield" setfield" getstatic" setstatic Stack Flow Control Boolean and Numeric Array Access *aload" *astore" b,s,c,i,l,d,f,a Local Vars Allocation
  71. 71. 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
  72. 72. A User-definable Bytecode You decide how the JVM implements it + Method Pointers and Adapters Faster than reflection, with user-defined argument, flow, and exception handling
  73. 73. invokedynamic opcode user-def’d bytecode method pointers MethodHandles invokedynamic
  74. 74. Method Invocation VM Operations Method Lookup Type Checking Branch Method Cache obj.foo() Target Object JVM Call Site instanceof Object’s Class void foo() void foo() static void bar()
  75. 75. // 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)
  76. 76. // 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
  77. 77. invokevirtual" 1. Confirm object is of correct type 2. Confirm arguments are of correct type 3. Look up method on Java class invokestatic 4. Cache method 5. Invoke method invokestatic" 1. Confirm arguments are of correct type 2. Look up method on Java class 3. Cache method 4. Invoke method invokevirtual invokeinterface" 1. Confirm object’s type implements interface 2. Confirm arguments are of correct type 3. Look up method on Java class invokeinterface 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 invokespecial invokedynamic! 1. Call bootstrap handle (your code) 2. Bootstrap prepares CallSite + MethodHandle 3. MethodHandle invoked now and future (until CallSite changes)
  78. 78. invokedynamic bytecode target method bo ot st ra p m et ho d method handles
  79. 79. How Do You Benefit?
  80. 80. Indy Languages • New language impls • JavaScript: Dyn.js and Nashorn • Redline Smalltalk • Improved language performance • JRuby, Groovy, Jython • Java features too!
  81. 81. JRuby/Java 6 JRuby/Java 7 Times Faster than Ruby 1.9.3 5 4.32 3.75 3.66 3.44 2.5 2.658 1.914 1.25 0 1.346 base64 1.565 1.538 richards neural redblack
  82. 82. red/black tree, pure Ruby versus native ruby-2.0.0 + Ruby 2.48s ruby-2.0.0 + C ext 0.51s jruby + Ruby 0.29s 0 0.75 1.5 Runtime per iteration 2.25 3
  83. 83. 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…
  84. 84. Feeling Helpless?
  85. 85. JVM Language JVM Bytecode Out of our control Written in C++ Bytecode Interpreter Bytecode JIT Native Code
  86. 86. 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
  87. 87. 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/
  88. 88. JVM Language Plain Java APIs Graal Intermediate Representation Graal Optimizer Under your control Your Transformations Your Optimizations Native Code
  89. 89. 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
  90. 90. The Dream • Design your language • ??? • PROFIT
  91. 91. Without JVM • Design your language • Work out memory model • Create an optimizing compiler • Spend ten years debugging it • PROFIT
  92. 92. With JVM • Design your language • Maybe write an interpreter • Compile to JVM bytecode • Pray that the JVM optimizes it right • PROFIT
  93. 93. What We Want • Design your language • ??? • PROFIT
  94. 94. What We Want • Design your language • Write an interpreter • PROFIT
  95. 95. 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
  96. 96. Traditional Approach Guest Language AST interpreter in pure Java Custom made bytecode compiler Bytecode emitted by guest language Any JVM
  97. 97. Truffle Atop JVM Guest Language AST interpreter in pure Java Truffle Bytecode based on interpreter flow Any JVM
  98. 98. Truffle Atop Graal Guest Language AST interpreter in pure Java Truffle Direct access to compiler internals, IR, machine code cache, on stack replacement, etc etc Graal JVM
  99. 99. 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
  100. 100. Thank you! • Charles Oliver Nutter • @headius, headius@headius.com • http://blog.headius.com
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