project panama - beyond the (jvm) wall

https://middleofnowheregaming.files.wordpress.com/2015/04/game-of-thrones_20150327091828.jpg

Project PanamaBeyond the (JVM) Wall

www.hazelcast.com@noctarius2k

DisclaimerThis is not a rant - promised!

Just a little bit about JNI ;-)


Disclaimer #2If you haven’t seen Game of Thrones yet

keep your eyes closed!


Disclaimer #3Everything is provisional

Don’t take anything as final!


Who’s that dude?• Chris Engelbert • Manager of Developer Relations @Hazelcast

• Java-Passionate (10+ years)

• Performance • Garbage Collection • JVM / Benchmark Fairytales


I drink and I know things (sometimes)


Project Panama

The True Native Love


Unite Enemies

C/C++Java


JNI! That's a good name for you!


JNI brings interaction between native code and Java

#include <unistd.h>int pid = getpid();

simple kernel call




simple kernel call header import




simple kernel call header import

request PID



Isn’t that easy in C?


You know nothing, of JNI!


Starting with the C part :-)



extern C { JNIEXPORT int JNICALL Java_ProcessIdentifier_getProcessId(JNIEnv *, jobject);}




export it as a JNI method





Java Classname





Java Classname Java Methodname




JNIEXPORT int JNICALLJava_ProcessIdentifier_getProcessId(JNIEnv *env, jobject thisObject) { return getpid();}





kernel call


When you think you just won…




Starting with the C part :-)JNIEXPORT jint JNICALLJNI_OnLoad(JavaVM *vm, void *reserved) { return JNI_VERSION_1_2;}




Starting with the C part :-)JNIEXPORT jint JNICALLJNI_OnLoad(JavaVM *vm, void *reserved) { return JNI_VERSION_1_2;}

JNI version definition




done, easy right?JNIEXPORT jint JNICALLJNI_OnLoad(JavaVM *vm, void *reserved) { return JNI_VERSION_1_2;}




oh, missing the Java side, stillJNIEXPORT jint JNICALLJNI_OnLoad(JavaVM *vm, void *reserved) { return JNI_VERSION_1_2;}

public class ProcessIdentifier { static { System.loadLibrary("processidentifier"); }

public native void getProcessId();}







Java Classname




ok, ok, now we’re done!JNIEXPORT jint JNICALLJNI_OnLoad(JavaVM *vm, void *reserved) { return JNI_VERSION_1_2;}




Wasn’t that easy?


Wasn’t that easy?

but remember…


Everybody struggles with JNI!


meanwhile behind the wall…


Java 9 to the rescue



long pid = ProcessHandle.current().getPid();



long pid = ProcessHandle.current().getPid();

convenient, eh?


but how many can just update?


So? JNI?


So? JNI? - NO!


A Song From Methods And Handles


MethodHandlesMethodType type = MethodType.methodType(int.class);MethodHandle mh = MethodHandles.lookup() .findVirtual(ProcessIdentifier.class, "getProcessId", type);

int pid = mh.invokeExact();




type definition




returntypetype definition





Java Classname





Java Classname Java Methodnamecall the new callsite


MethodHandles

So? What’s the deal? Java 7, right?




virtual call


MethodHandlesMethodType type = MethodType.methodType(int.class);MethodHandle mh = MethodHandles.lookup() .findNative(null, "getpid", type);


native




native

native call




native

native call null = kernel callotherwise lib name


Easier than takingthe Iron Throne!


The Mad King


Pointer with sun.misc.Unsafe

Unsafe unsafe = getUnsafeWithMagic();long ptr = unsafe.allocateMemory(20);byte val = unsafe.getByte(ptr + 5);




retrieve sun.misc.Unsafe instance





allocate 20 bytes





allocate 20 bytesget byte at ptr+5


So I die, for using Unsafe?


Who needs Unsafe anywaysLayoutType<Byte> layout = NativeLibrary.createLayout(byte.class);

try (Scope scope = new NativeScope()) { Pointer<Byte> p = scope.allocate(layout, 20); Reference<Byte> ref = p.offset(5).deref(); byte val = ref.get();}




byte-arraylayout




byte-arraylayout

create ascope




byte-arraylayout

create ascope

allocate 20 bytes




byte-arraylayout

create ascope

allocate 20 bytesget byte at ptr+5


Who needs Unsafe anyways


A REAL NULL POINTER! THANK YOU JAVA!

Who needs Unsafe anyways


About Structs and other Creatures


Struct in Java? No, Layout!

typedef struct { int32_t val; Node next;} Node;


Same LinkedList Node in Java

@LayoutDesc({"x:jint:4", "y:Node:8"})public interface Node extends Layout { // …}


@LayoutDesc({"x:jint:4", "y:Node:8"})public interface Node extends Layout { interface EffectiveAddress { IntPointer val(); Pointer<Node> next(); } // …}



@LayoutDesc({"x:jint:4", "y:Node:8"})public interface Node extends Layout { Node.EffectiveAddress EA(); long sizeof(); int val(); // …}



@LayoutDesc({"x:jint:4", "y:Node:8"})public interface Node extends Layout { Node next(); void val(int val); void next(Node next); String toString();}



Scope scope = new NativeScope();Pointer<Node> ptr = scope.allocate(Node.class);Node node = ptr.getLayout();int val = node.val();Node next = node.next();

Creating layouted Objects


I slayed the Mad King


Value Isn’t A Pit. Value Is A Ladder.


Value Types

value class Point { int x; int y;}


Value Types

Point point = __make Point(1, 2);int x = point.x;int y = point.y;


Yet another layout?


class Point {}Point[] points = …

Arrays of Points


value class Point {}Point[] points = …

Arrays of Points


I’m feeling so Assembler today


Coding a Vector-Function in JavaMethodType type = MethodType.methodType( Float.class, Float.class, Float.class);

MethodHandle m256_vadds = CodeSnippets .make(..., type, …);

m256_vadds.invokeExact(out, in1, in2);

low-level


Coding a Vector-Function in Javahigh-level

interface Vector<E, S extends Shape<Vector?, S>> { Vector<E, S> add (Vector<E, S> other); Vector<E, S> mul (Vector<E, S> other); Vector<E, S> and (Vector<E, S> other); // ... more operations}



void addVector(float[] left, float[] right, float[] res, int length) { // …}



void addVector(float[] left, float[] right, float[] res, int length) { FloatVector<S256Bit> l = float256FromArray(left, length); FloatVector<S256Bit> r = float256FromArray(right, length); // …}



void addVector(float[] left, float[] right, float[] res, int length) { // … FloatVector<S256Bit> lr = l.add(r); lr.intoArray(res, length);}


Razersharp tooling


So what do we expect?


Peace with the Dragons


Peace with the DragonsC / C++


Painless communication…


Painless communication…

…between native and Java code


More fun…


More fun…

… and faster code …


More fun…

…without JNI

… and faster code …


Thank You &George R.R. Martin


More information:• http://openjdk.java.net/projects/valhalla/ • http://openjdk.java.net/projects/panama/ • http://cr.openjdk.java.net/~jrose/values/values-0.html • http://blog.codefx.org/java/dev/the-road-to-valhalla/ • http://openjdk.java.net/jeps/191 • https://www.youtube.com/watch?v=JR1zI5gLhRM • https://github.com/J9Java/panama-layout-prototype • https://developer.ibm.com/open/openprojects/project-panama-layout-prototype/ • https://www.youtube.com/watch?v=Tc9vs_HFHVo • https://www.youtube.com/watch?v=Z2XgO1H6xPM

Thank You!


Thank You!Any Questions?

@noctarius2k http://www.sourceprojects.org

http://github.com/noctarius

@hazelcast http://www.hazelcast.com http://www.hazelcast.org

http://github.com/hazelcast


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project panama - beyond the (jvm) wall

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