There are lots of good things about working on the JVM, like a world class JIT, operating system threads, and a world class garbage collector. However, one limiting factor can often be the interaction between primitive types and referenced types in Java. Primitive types are the built in types that represent integral numbers, floating point numbers, and boolean yes/no values. Primitives are also quite fast and memory efficient: they get allocated either on the stack if they're being used in a method, or inlined in an object when they're declared as field members. And they wind up being fast because the JIT can often optimize their access down to a single CPU instruction. This works really well when you know what types a class will hold as its state beforehand. If, on the other hand, you don't know what an object or array will hold at compile time the JVM forces you to box primitives. Boxing means that the primitives get wrapped in a heap allocated object, and their container will hold a reference to them. That type of overhead winds up being inefficient both in access time and memory space. Access time suffers because this type of layout breaks locality of reference, which is the principle that memory frequently accessed together should be stored adjacently. All modern memory hierarchies optimize for locality of reference in their caching implementations. The extra allocations and garbage generated also put pressure on the JVM's garbage collector, which can often be a cause of long pause times.
We wrote FastTuple to try and help solve this problem. FastTuple generates heterogeneous collections of primitive values and ensures as best it can that they will be laid out adjacently in memory. The individual values in the tuple can either be accessed from a statically bound interface, via an indexed accessor, or via reflective or other dynamic invocation techniques. FastTuple is designed to deal with a large number of tuples therefore it will also attempt to pool tuples such that they do not add significantly to the GC load of a system. FastTuple is also capable of allocating the tuple value storage entirely off-heap, using Java's direct memory capabilities.
FastTuple pulls off its trick via runtime bytecode generation. The user supplies it with a schema of field names and types. That schema is then built into a Java class definition which will contain accessor methods and either field definitions or the memory address for an off heap allocation, depending on which storage method was requested. The resulting Java class gets compiled into bytecode and then loaded as a reflective Class object. This Class object can then be used to create instances of the new class.
This package depends on Janino 2.7.4, which is not currently getting pushed to maven central. As soon as that happens (we have a ticket in with the maintainer) we will begin pushing FastTuple to maven central as well. In the meantime you can build FastTuple like so:
wget http://janino.net/download/janino-2.7.4.zip unzip janino-2.7.4.zip mvn install:install-file -Dfile=janino-2.7.4/janino.jar -Dsources=janino-2.7.4/janino-src.zip -DgroupId=org.codehaus.janino -DartifactId=janino -Dversion=2.7.4 -Dpackaging=jar mvn install:install-file -Dfile=janino-2.7.4/commons-compiler.jar -Dsources=janino-2.7.4/commons-compiler-src.zip -DgroupId=org.codehaus.janino -DartifactId=commons-compiler -Dversion=2.7.4 -Dpackaging=jar mvn install
Note on GPG
You'll also need to ensure that you have GPG available on the command line. Mac OS X and Windows users may need to install via (https://gpgtools.org/) or cygwin respectively.
Interaction with FastTuple primarily takes place via the TupleSchema class. Each instance of TupleSchema describes a separate type of FastTuple both from the perspective of the FastTuple library and the JVM. At this time, allowable field types are the primitive classes for: long, int, short, char, byte, float, double. Support for String is planned for a later release. Some examples:
Heap Allocated Tuples
TupleSchema schema = TupleSchema.builder(). addField("fieldA", Long.TYPE). addField("fieldB", Int.TYPE). addField("fieldC", Short.TYPE). heapMemory(). build(); //creates a new tuple allocated on the JVM heap FastTuple tuple = schema.createTuple();
Direct Allocated Tuples
TupleSchema schema = TupleSchema.builder(). addField("fieldA", Long.TYPE). addField("fieldB", Int.TYPE). addField("fieldC", Short.TYPE). directMemory(). build(); //creates a new tuple, allocating memory off heap FastTuple tuple = schema.createTuple(); //do some stuff tuple.setLong(1, 10000L); tuple.setInt(2, 50); tuple.setShort(3, (short)256); //if you don't destroy the tuple you are leaking memory schema.destroy(tuple);
Aligning Direct Allocated Tuples
Direct allocated tuples can be aligned such that they do not share cache lines. This is useful for situations where adjacent tuples are manipulated concurrently by different threads: an adequately padded FastTuple can eliminate false sharing in the CPU cache architecture. Veriifying that property, as expected, will require extensive benchmarking inside of the target system.
TupleSchema schema = TupleSchema.builder(). addField("fieldA", Long.TYPE). addField("fieldB", Int.TYPE). addField("fieldC", Short.TYPE). directMemory(). padToWordSize(64). build(); //creates a new tuple, allocating memory off heap FastTuple tuple = schema.createTuple(); //do some stuff tuple.setLong(1, 10000L); tuple.setInt(2, 50); tuple.setShort(3, (short)256); //if you don't destroy the tuple you are leaking memory schema.destroy(tuple);
Utilizing Tuple Pools
Each schema will allocate a tuple pool per accessing thread if a poolSize is set.
TupleSchema schema = TupleSchema.builder(). addField("fieldA", Long.TYPE). addField("fieldB", Int.TYPE). addField("fieldC", Short.TYPE). poolOfSize(1024). //allocates an extra poolOfSize records when the pool is empty .expandingPool(). build(); //checks a tuple from the pool FastTuple tuple = schema.pool().checkout(); //do some stuff tuple.setLong(1, 10000L); tuple.setInt(2, 50); tuple.setShort(3, (short)256); //if you don't check the tuple back in you either leak memory or objects. bad dog. schema.pool().release(tuple);
One of the main goals of this library is performance. Toward that end it has a full suite of microbenchmarks to test the various supported means of accessing and manipulating tuples for both tuning the library and showing the tradeoffs in overhead for things like pooling and allocating tuples on demand. Here's what a full run looks like on a late 2013 macbook pro 2.6ghz with Java 8 1.8.0_05-b13.
Benchmark Mode Samples Mean Mean error Units c.b.t.AccessMethodBenchmark.testAllocateSetAndDeallocate thrpt 20 7069.954 181.689 ops/ms c.b.t.AccessMethodBenchmark.testClass thrpt 20 1628847.332 21756.564 ops/ms c.b.t.AccessMethodBenchmark.testFastPool thrpt 20 30715.791 570.086 ops/ms c.b.t.AccessMethodBenchmark.testFastTuplePreAllocIndexed thrpt 20 160173.234 2498.380 ops/ms c.b.t.AccessMethodBenchmark.testFastTuplePreAllocIndexedBoxing thrpt 20 59117.984 630.813 ops/ms c.b.t.AccessMethodBenchmark.testFastTupleStaticBinding thrpt 20 157928.877 2411.094 ops/ms c.b.t.AccessMethodBenchmark.testInvokeDynamic thrpt 20 26085.594 1158.292 ops/ms c.b.t.AccessMethodBenchmark.testLongArray thrpt 20 1721846.666 23422.990 ops/ms c.b.t.AccessMethodBenchmark.testOffheapAllocateAndSet thrpt 20 7512.737 167.141 ops/ms c.b.t.AccessMethodBenchmark.testOffheapDirectSet thrpt 20 898743.426 37659.166 ops/ms c.b.t.AccessMethodBenchmark.testOffheapSchemaSet thrpt 20 367841.110 4282.620 ops/ms c.b.t.AccessMethodBenchmark.testPooledObject thrpt 20 12572.464 155.458 ops/ms c.b.t.AccessMethodBenchmark.testQueuedObject thrpt 20 25092.751 242.771 ops/ms c.b.t.AccessMethodBenchmark.testReflectField thrpt 20 28850.478 275.462 ops/ms c.b.t.AccessMethodBenchmark.testStormTuple thrpt 20 79693.517 888.956 ops/ms c.b.t.AccessMethodBenchmark.testTuplePool thrpt 20 70790.084 950.775 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaAllocate thrpt 20 7214.300 98.387 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaDeque thrpt 20 153937.210 2534.986 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPoolEval thrpt 20 53563.512 836.586 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPoolIface thrpt 20 57669.480 716.962 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPoolIndexed thrpt 20 57633.447 1025.338 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPoolIndexedBoxed thrpt 20 38984.939 823.182 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPreallocEval thrpt 20 332142.591 6426.566 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPreallocIface thrpt 20 370593.271 5369.162 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPreallocIndexed thrpt 20 377811.881 7077.471 ops/ms c.b.t.FastTupleBenchmarks.DirectBenchmarks.measureDirectSchemaPreallocIndexedBoxed thrpt 20 115699.056 2402.657 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaAllocate thrpt 20 990788.476 12295.764 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaDeque thrpt 20 173527.417 3619.733 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPoolEval thrpt 20 59377.121 1071.014 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPoolIface thrpt 20 62391.209 765.821 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPoolIndexed thrpt 20 62120.412 1105.981 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPoolIndexedBoxed thrpt 20 42187.554 737.124 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPreallocEval thrpt 20 397337.746 5274.807 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPreallocEvalField thrpt 20 579136.768 8818.827 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPreallocIface thrpt 20 554449.236 6740.073 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPreallocIndexed thrpt 20 536258.735 10417.522 ops/ms c.b.t.FastTupleBenchmarks.HeapBenchmarks.measureHeapSchemaPreallocIndexedBoxed thrpt 20 202220.576 3806.694 ops/ms
To run the benchmarks:
mvn package java -jar fasttuple-bench/target/microbenchmarks.jar