Download public static final

Beyond JVM
or, How to Boil the Ocean in Seven Years
+
We Like the JVM
No platform-specific
compilation needed.
No native library
dependencies
Optimizing JIT compiler
Magical black box that
runs our code
Things We Like About
JVM
• Bytecode intermediate form
• Freedom from native libraries
• Optimizing JIT
• It just works (usually)
Things That Make
JRuby Difficult
• Bytecode intermediate form
• Optimizing JIT
• Freedom from native libraries
• It just works (usually)
Things That Make
JRuby Difficult
• Startup time sucks
• JNI is a massive pain to use
• Hard to get unusual languages to optimize
• Core is in C++ that we can’t touch
There must be a way!
Startup Time
Java-Heavy JDK
• + Less native code to maintain
• + Easier portability
• + Easier to swap out native side
• – Takes longer to warm up
JVM
Language
JVM
Bytecode
Bytecode
Interpreter
Bytecode
JIT
Time
Native
Code
JVM
Language
JVM
Bytecode
Bytecode
Interpreter
Bytecode
JIT
Native
Code
Save JITed Code?
• Code will change across runs
• Often has specific memory addresses
• May optimize object layout differently
• Which JIT output?
• Client, Server, Tiered (1-4)
JRuby Startup
C Ruby
JRuby
-e 1
gem --help
rake -T
0
2.5
5
7.5
10
Tweaking Flags
• -client mode
• -XX:+TieredCompilation -XX:TieredStopAtLevel=1
• -X-C to disable JRuby’s compiler
• Heap sizes, code verification, etc etc
JRuby Startup
C Ruby
JRuby
JRuby (best)
-e 1
gem --help
rake -T
0
2.5
5
7.5
10
Nailgun?
• Keep a single JVM running in background
• Toss commands over to it
• It stays hot, so code starts faster
• Hard to clean up all state (e.g. threads)
• Can’t get access to user’s terminal
Drip
• Start a new JVM after each command
• Pre-boot JVM plus optional code
• Analyze command line for differences
• Age out unused instances
• https://github.com/flatland/drip
$ export JAVACMD=`which drip`
!
$ time jruby -e 1
!
real 0m1.655s
user 0m4.486s
sys0m0.231s
!
$ time jruby -e 1
!
real 0m0.577s
user 0m0.052s
sys0m0.065s
JRuby Startup
C Ruby
JRuby
JRuby (best)
JRuby (drip)
-e 1
gem --help
rake -T
0
2.5
5
7.5
10
$ export DRIP_INIT_CLASS=org.jruby.main.DripMain
!
$ export DRIP_INIT=""
!
$ time jruby -e 1
!
real 0m0.580s
user 0m0.052s
sys0m0.063s
!
$ time jruby -e 1
!
real 0m0.155s
user 0m0.049s
sys0m0.058s
public class DripMain {!
public static RubyInstanceConfig DRIP_CONFIG;!
public static Ruby DRIP_RUNTIME;!
!
public static final String JRUBY_DRIP_WARMUP_ENV = "JRUBY_DRIP_WARMUP";!
public static final String JRUBY_DRIP_WARMUP_DEFAULT = "1 + 1";!
public static final String JRUBY_DRIP_PREBOOT_FILE = "./dripmain.rb";!
!
public static void main(String[] args) throws IOException {!
// warmup JVM first!
Ruby ruby = Ruby.newInstance();!
!
String envWarmup = System.getenv(JRUBY_DRIP_WARMUP_ENV);!
if (envWarmup != null && envWarmup.length() > 0) {!
ruby.evalScriptlet(envWarmup);!
} else {!
ruby.evalScriptlet(JRUBY_DRIP_WARMUP_DEFAULT);!
}!
!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
!
if (dripMain.exists()) {!
FileInputStream fis = new FileInputStream(dripMain);!
try {!
ruby.getLoadService().load(dripMain.getAbsolutePath(), false);!
} finally {!
fis.close();!
}!
}!
!
// use config and runtime from preboot process!
DRIP_CONFIG = config;!
DRIP_RUNTIME = ruby;!
}!
}!
public static final String JRUBY_DRIP_WARMUP_ENV = "JRUBY_DRI
public static final String JRUBY_DRIP_WARMUP_DEFAULT = "1 + 1
public static final String JRUBY_DRIP_PREBOOT_FILE = "./dripm
public static void main(String[] args) throws IOException {!
// warmup JVM first!
Ruby ruby = Ruby.newInstance();!
String envWarmup = System.getenv(JRUBY_DRIP_WARMUP_ENV);!
if (envWarmup != null && envWarmup.length() > 0) {!
ruby.evalScriptlet(envWarmup);!
} else {!
ruby.evalScriptlet(JRUBY_DRIP_WARMUP_DEFAULT);!
}!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
public static final String JRUBY_DRIP_WARMUP_ENV = "JRUBY_DRI
public static final String JRUBY_DRIP_WARMUP_DEFAULT = "1 + 1
public static final String JRUBY_DRIP_PREBOOT_FILE = "./dripm
public static void main(String[] args) throws IOException {!
// warmup JVM first!
Ruby ruby = Ruby.newInstance();!
String envWarmup = System.getenv(JRUBY_DRIP_WARMUP_ENV);!
if (envWarmup != null && envWarmup.length() > 0) {!
ruby.evalScriptlet(envWarmup);!
} else {!
ruby.evalScriptlet(JRUBY_DRIP_WARMUP_DEFAULT);!
}!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
public static final String JRUBY_DRIP_WARMUP_ENV = "JRUBY_DRI
public static final String JRUBY_DRIP_WARMUP_DEFAULT = "1 + 1
public static final String JRUBY_DRIP_PREBOOT_FILE = "./dripm
public static void main(String[] args) throws IOException {!
// warmup JVM first!
Ruby ruby = Ruby.newInstance();!
String envWarmup = System.getenv(JRUBY_DRIP_WARMUP_ENV);!
if (envWarmup != null && envWarmup.length() > 0) {!
ruby.evalScriptlet(envWarmup);!
} else {!
ruby.evalScriptlet(JRUBY_DRIP_WARMUP_DEFAULT);!
}!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
if (dripMain.exists()) {!
FileInputStream fis = new FileInputStream(dripMain);!
try {!
ruby.getLoadService().load(dripMain.getAbsolutePa
} finally {!
fis.close();!
}!
}!
// use config and runtime from preboot process!
DRIP_CONFIG = config;!
DRIP_RUNTIME = ruby;!
}!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
if (dripMain.exists()) {!
FileInputStream fis = new FileInputStream(dripMain);!
try {!
ruby.getLoadService().load(dripMain.getAbsolutePa
} finally {!
fis.close();!
}!
}!
// use config and runtime from preboot process!
DRIP_CONFIG = config;!
DRIP_RUNTIME = ruby;!
}!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
if (dripMain.exists()) {!
FileInputStream fis = new FileInputStream(dripMain);!
try {!
ruby.getLoadService().load(dripMain.getAbsolutePa
} finally {!
fis.close();!
}!
}!
// use config and runtime from preboot process!
DRIP_CONFIG = config;!
DRIP_RUNTIME = ruby;!
}!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
if (dripMain.exists()) {!
FileInputStream fis = new FileInputStream(dripMain);!
try {!
ruby.getLoadService().load(dripMain.getAbsolutePa
} finally {!
fis.close();!
}!
}!
// use config and runtime from preboot process!
DRIP_CONFIG = config;!
DRIP_RUNTIME = ruby;!
}!
// preboot actual runtime!
Ruby.clearGlobalRuntime();!
File dripMain = new File(JRUBY_DRIP_PREBOOT_FILE);!
RubyInstanceConfig config = new RubyInstanceConfig();!
ruby = Ruby.newInstance(config);!
if (dripMain.exists()) {!
FileInputStream fis = new FileInputStream(dripMain);!
try {!
ruby.getLoadService().load(dripMain.getAbsolutePa
} finally {!
fis.close();!
}!
}!
// use config and runtime from preboot process!
DRIP_CONFIG = config;!
DRIP_RUNTIME = ruby;!
}!
JRuby Startup
C Ruby
JRuby (drip init)
JRuby
JRuby (best)
JRuby (drip)
-e 1
gem --help
rake -T
0
2.5
5
7.5
10
$ cat dripmain.rb
# Preload some code Rails always needs
require File.expand_path('../config/application', __FILE__)
JRuby Startup
C Ruby
JRuby (drip)
JRuby
JRuby (drip init)
JRuby (best)
JRuby (dripmain)
rake -T
0
2.5
5
7.5
10
JRuby Startup
C Ruby
JRuby (dripmain)
rake -T
0
0.275
0.55
0.825
1.1
Native Interop
JVM World
????
Native World
JNI
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();!
}!
!
static {!
System.load(!
System.getProperty("user.dir") +!
"/getpidjni.dylib");!
}!
}
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
JNI
#include "com_headius_jnr_presentation_GetPidJNI.h"!
!
jlong JNICALL Java_com_headius_jnr_1presentation_GetPidJNI_getpid!
(JNIEnv *env, jclass c) {!
!
return getpid();!
}
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
There Must Be
A Better Way
User Code
Java
JNI call
C/native
JNI impl
Target Library
User Code
Java
JNI call
C/native
JNI impl
Target Library
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
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 interface GetPid {!
long getpid();!
}!
!
public static void main( String[] args ) {!
GetPid getpid = LibraryLoader!
.create(GetPid.class)!
.load("c");!
!
getpid.getpid();!
}!
}
Layered Runtime
etc etc
jnr-posix
jnr-unixsocket!
jnr-enxio
jnr-constants
jnr-ffi
jffi
libffi
jnr-x86asm
jffi 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
jnr-ffi
• User-oriented API
• Roughly equivalent to what JNA gives you
• Functions, structs, callbacks, memory
• https://github.com/jnr/jnr-ffi
jnr-posix
• Pre-bound set of POSIX functions
• Mostly driven by what JRuby, Jython use
• Goal: 100% of POSIX bound to Java
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);
POSIX posix = POSIXFactory.getPOSIX(!
new MyPOSIXHandler(this),!
isNativeEnabled);
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();!
}
public
public
public
public
public
public
public
public
public
int chmod(String string, int i);!
int chown(String string, int i, int i1);!
int kill(int i, int i1);!
int getpriority(int i, int i1);!
int setpriority(int i, int i1, int i2);!
int waitpid(int i, int[] ints, int i1);!
int wait(int[] ints);!
int errno();!
void errno(int i);
jnr-constants
• C/preprocessor constants in enum form
• Generator code to run on each platform
• Several pregenerated sets for jnr-posix
public int open(String string, int flags, int mode);!
public int socket(int i, int i1);
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
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;!
}
jnr-unixsocket
• UNIX sockets for NIO
• Built atop jnr-enxio
• Fully selectable, etc
• https://github.com/jnr/jnr-unixsocket
What Else?
• 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, ...)
How Does It Perform?
Performance
• Generated code leading to JNI call
• Generated assembly version of native part
• jnr-x86asm: Generate and link ASM
• Used internally by jnr
• https://github.com/jnr/jnr-x86asm
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 {!
public interface GetPid {!
@IgnoreError!
long getpid();!
}!
!
public static void main( String[] args ) {!
GetPid getpid = LibraryLoader!
.create(GetPid.class)!
.load("c");!
!
getpid.getpid();!
}!
}
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 call directly at call site
• Security policies, segv protection, etc
• Time for an FFI JSR
Language Performance
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
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
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
Invoke
// Static!
System.currentTimeMillis()!
Math.log(1.0)
Invoke
// Static!
System.currentTimeMillis()!
Math.log(1.0)!
!
// Virtual!
"hello".toUpperCase()!
System.out.println()
Invoke
// Static!
System.currentTimeMillis()!
Math.log(1.0)!
!
// Virtual!
"hello".toUpperCase()!
System.out.println()!
!
// Interface!
myList.add("happy happy")!
myRunnable.run()
Invoke
// Static!
System.currentTimeMillis()!
Math.log(1.0)!
!
// Virtual!
"hello".toUpperCase()!
System.out.println()!
!
// Interface!
myList.add("happy happy")!
myRunnable.run()!
!
// Constructor and super!
new ArrayList()!
super.equals(other)
// 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
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 your bootstrap code
2. Bootstrap wires up a target function
3. Target function invoked directly until you change it
invokedynamic bytecode
target method
bo
ot
st
ra
p
m
et
ho
d
method handles
Does It Work?
Indy Languages
• New language impls
• JavaScript: Dyn.js and Nashorn
• Redline Smalltalk
• Improved language performance
• JRuby, Groovy, Jython
• Java features too!
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
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
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…
All That C++
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 library
• JITed code could directly make native calls
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/
JVM
Language
Plain Java APIs
Graal
Intermediate
Representation
Graal
Optimizer
Your
Optimizations
Under your control
Native
Code
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
The Dream
• 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 that to backend
• No compiler expertise needed
• https://wiki.openjdk.java.net/display/Graal/Truffle+FAQ+and+Guidelines
JVM
Language
Truffle
AST
All we need
Graal
Intermediate
Representation
Graal
Optimizer
Native
Code
What Have We Learned?
The JVM has its
problems, but we can
fix them.
OpenJDK and all these
solutions are really,
truly, open source.
Nothing is impossible.
Thank you!
• Charles Oliver Nutter
• @headius, [email protected]
• http://blog.headius.com