The document discusses the Disruptor, a high performance inter-thread messaging library created by LMAX. It introduces key concepts like the ring buffer, producer-consumer pattern, and consumer dependency graphs. It then explains the Disruptor architecture which uses a multithreaded producer to populate a ring buffer of event data which is consumed by handler threads in a specified order without blocking. Finally, it outlines examples of unicast, multicast and pipelined consumer configurations and references additional resources to learn more about the Disruptor and related concurrency concepts.

1. DISRUPTOR
Larry Nung

2. AGENDA
Introduction
Relative Technologies
Disruptor
LMAX Architecture
Reference
Q & A
2

3. INTRODUCTION

4. INTRODUCTION
 High Performance Inter-Thread Messaging Library
 LMAX build the system on the JVM platform and
centers on a Business Logic Processor that can
handle 6 million orders per second on a single
thread with very low latency: 100K TPS with 1 ms
latency.
 Multicast events to consumers, with consumer
dependency graph.
 Pre-allocate memory for events.
 Optionally lock-free.

5. RELATIVE TECHNOLOGIES

6. CAS
 Compare-and-swap
 An atomic instruction used in multithreading to
achieve synchronization
56
Core1 Core2
56=>57 55=>58

7. CAS

8. MEMORY BARRIERS
 A type of barrier instruction that causes a central
processing unit (CPU) or compiler to enforce an
ordering constraint on memory operations issued
before and after the barrier instruction.

9. CACHE LINE
 Unit of transfer between memory and CPU
 Cache-Lines size is (typically) 64 bytes.

10. FALSE SHARING
 When a system participant attempts to periodically
access data that will never be altered by another
party, but that data shares a cache block with data
that is altered, the caching protocol may force the
first participant to reload the whole unit despite a
lack of logical necessity.

11. FALSE SHARING
struct foo { int x; int y; };
static struct foo f;
/* The two following functions are running concurrently: */
int sum_a() {
int s = 0;
int i;
for (i = 0; i < 1000000; ++i)
s += f.x;
return s;
}
void inc_b() {
int i;
for (i = 0; i < 1000000; ++i)
++f.y;
}

12. CACHE LINE PADDING

13. DISRUPTOR

14. DISRUPTOR ARCHITECTURE
 Ring buffer size = 2 ^ n
 Index = sequence & (bufferSize - 1)
 no comparisons
 no branches
 safe
Producer
Consumer

15. CONSUMER DEPENDENCY GRAPH
 Unicast: 1P - 1C
 Three Step Pipeline: 1P – 3C
P1 C1
P1 C1 C2 C3
P1
C1
P1
C1
C2
C3

16. CONSUMER DEPENDENCY GRAPH
 Sequencer: 3P – 1C
 Multicast: 1P – 3C
P1
P2
P3
C1
P1
C1
C2
C3
P1
C1
P2
P3
P1
C1
C2
C3

17. CONSUMER DEPENDENCY GRAPH
 Diamond: 1P – 3C
P1
C1
C2
C3
P1
C1
C2
C3

18. CONSUMER DEPENDENCY GRAPH

19. WAIT STRATEGY
 BlockingWaitStrategy
 BusySpinWaitStrategy
 SleepingWaitStrategy
 TimeoutBlockingWaitStrategy
 PhasedBackoffWaitStrategy
 YieldingWaitStrategy

20. SETUP DISRUPTOR

21. CUSTOM EVENTHANDLER
...
public class Data {
public string Value { get; set; }
}
public class DataEventHandler : IEventHandler<Data>
{
public string Name { get; private set; }
public DataEventHandler(string name) {
this.Name = name;
}
public void OnEvent(Data data, long sequence, bool endOfBatch) {
Console.WriteLine("Thread = {0}, Handler = {1}, Sequence = {2}, Value
= {3}", Thread.CurrentThread.ManagedThreadId.ToString(), this.Name,
sequence, data.Value);
}
}
...

22. DSL
Generate disruptor
instance with factory
method and ring buffer
size
Setup consumer
dependency graph with
Disruptor.HandleEvents
With
Start disruptor with
Disruptor.Start
Get ring buffer
Get next ring buffer
sequence
Set data
Publish data

23. DSL
...
var disruptor = new Disruptor.Dsl.Disruptor<Data>(() => new Data(), (int)Math.Pow(2,4),
TaskScheduler.Default);
disruptor.HandleEventsWith(new DataEventHandler("Handler1"));
var ringBuffer = disruptor.Start();
var sequenceNo = ringBuffer.Next();
var data = ringBuffer[sequenceNo];
data.Value = "Hello";
ringBuffer.Publish(sequenceNo);
sequenceNo = ringBuffer.Next();
data = ringBuffer[sequenceNo];
data.Value = "World";
ringBuffer.Publish(sequenceNo);
disruptor.Shutdown();
...

24. NON-DSL
Generate ring buffer with
factory method and ring
buffer size
Setup consumer
dependency graph with
EventProcessor And
Barrier
Start EventProcessor in
another thread
Get next ring buffer
sequence
Set dataPublish data

25. NON-DSL
...
var ringBuffer = RingBuffer<Data>.CreateSingleProducer(() => new Data(), (int)Math.Pow(2, 4));
var barrier = ringBuffer.NewBarrier();
var eventProcessor = new BatchEventProcessor<Data>(ringBuffer, barrier, new DataEventHandler("Handler1"));
Task.Factory.StartNew(() => eventProcessor.Run());
var sequenceNo = ringBuffer.Next();
var data = ringBuffer[sequenceNo];
data.Value = "Hello";
ringBuffer.Publish(sequenceNo);
sequenceNo = ringBuffer.Next();
data = ringBuffer[sequenceNo];
data.Value = "World";
ringBuffer.Publish(sequenceNo);
eventProcessor.Halt();
Application.DoEvents();
...

26. UNICAST: 1P - 1C
...
using Disruptor;
namespace ConsoleApplication29 {
…
class Program {
static void Main( string[] args) {
var disruptor = new Disruptor.Dsl. Disruptor<Data>(() => new Data(), (int)Math .Pow(2,4),
TaskScheduler.Default);
disruptor.HandleEventsWith(new DataEventHandler("Handler1”));
var ringBuffer = disruptor.Start();
var idx = 0;
while ( true) {
var sequenceNo = ringBuffer.Next();
var data = ringBuffer[sequenceNo];
data.Value = idx++.ToString();
ringBuffer.Publish(sequenceNo);
Thread.Sleep(250);
}
disruptor.Shutdown();
}
}
} P1 C1

27. UNICAST: 1P - 1C
...
var ringBuffer = RingBuffer<Data>.CreateSingleProducer(()
=> new Data(), (int)Math.Pow(2, 4));
var barrier = ringBuffer.NewBarrier();
var eventProcessor = new
BatchEventProcessor<Data>(ringBuffer, barrier, new
DataEventHandler("Handler1"));
Task.Factory.StartNew(() => eventProcessor.Run());
...
eventProcessor.Halt();
...
P1
Barrier
C1

28. UNICAST: 1P - 1C

29. THREE STEP PIPELINE: 1P – 3C
...
var disruptor = new Disruptor.Dsl.Disruptor<Data>(() =>
new Data(), (int)Math.Pow(2,4), TaskScheduler.Default);
disruptor.HandleEventsWith(new
DataEventHandler("Handler1"))
.Then(new DataEventHandler("Handler2"))
.Then(new DataEventHandler("Handler3"));
var ringBuffer = disruptor.Start();
...
disruptor.Shutdown();
…
P1 C1 C2 C3

30. THREE STEP PIPELINE: 1P – 3C
...
var ringBuffer = RingBuffer<Data>.CreateSingleProducer(() => new Data(),
(int)Math.Pow(2, 4));
var eventProcessor1 = new BatchEventProcessor<Data>(ringBuffer,
ringBuffer.NewBarrier(), new DataEventHandler("Handler1"));
var eventProcessor2 = new BatchEventProcessor<Data>(ringBuffer,
ringBuffer.NewBarrier(eventProcessor1.Sequence), new
DataEventHandler("Handler2"));
var eventProcessor3 = new BatchEventProcessor<Data>(ringBuffer,
ringBuffer.NewBarrier(eventProcessor2.Sequence), new
DataEventHandler("Handler3"));
Task.Factory.StartNew(() => eventProcessor1.Run());
Task.Factory.StartNew(() => eventProcessor2.Run());
Task.Factory.StartNew(() => eventProcessor3.Run());
...
eventProcessor1.Halt();
eventProcessor2.Halt();
eventProcessor3.Halt();
...
P1 C1 C2 C3
Barrier
Barrier
Barrier

31. THREE STEP PIPELINE: 1P – 3C

32. MULTICAST: 1P – 3C
...
var disruptor = new Disruptor.Dsl.Disruptor<Data>(() =>
new Data(), (int)Math.Pow(2,4), TaskScheduler.Default);
disruptor.HandleEventsWith(new
DataEventHandler("Handler1"), new
DataEventHandler("Handler2"), new
DataEventHandler("Handler3"));
var ringBuffer = disruptor.Start();
...
disruptor.Shutdown();
… P1
C1
C2
C3

33. MULTICAST: 1P – 3C
...
var ringBuffer = RingBuffer<Data>.CreateSingleProducer(() => new Data(), (int)Math.Pow(2, 4));
var barrier = ringBuffer.NewBarrier();
var eventProcessor1 = new BatchEventProcessor<Data>(ringBuffer, barrier, new
DataEventHandler("Handler1"));
var eventProcessor2 = new BatchEventProcessor<Data>(ringBuffer, barrier, new
DataEventHandler("Handler2"));
var eventProcessor3 = new BatchEventProcessor<Data>(ringBuffer, barrier, new
DataEventHandler("Handler3"));
Task.Factory.StartNew(() => eventProcessor1.Run());
Task.Factory.StartNew(() => eventProcessor2.Run());
Task.Factory.StartNew(() => eventProcessor3.Run());
...
eventProcessor1.Halt();
eventProcessor2.Halt();
eventProcessor3.Halt();
... P1
C1
C2
C3
Barrier

34. MULTICAST: 1P – 3C

35. DIAMOND: 1P – 3C
...
var disruptor = new Disruptor.Dsl.Disruptor<Data>(() =>
new Data(), (int)Math.Pow(2,4), TaskScheduler.Default);
disruptor.HandleEventsWith(new
DataEventHandler("Handler1"), new
DataEventHandler("Handler2")).Then(new
DataEventHandler("Handler3"));
var ringBuffer = disruptor.Start();
...
disruptor.Shutdown();
…
P1
C1
C2
C3

36. DIAMOND: 1P – 3C
...
var ringBuffer = RingBuffer<Data>.CreateSingleProducer(() => new Data(),
(int)Math.Pow(2, 4));
var barrier = ringBuffer.NewBarrier();
var eventProcessor1 = new BatchEventProcessor<Data>(ringBuffer, barrier, new
DataEventHandler("Handler1"));
var eventProcessor2 = new BatchEventProcessor<Data>(ringBuffer, barrier, new
DataEventHandler("Handler2"));
var eventProcessor3 = new BatchEventProcessor<Data>(ringBuffer,
ringBuffer.NewBarrier(eventProcessor1.Sequence, eventProcessor2.Sequence),
new DataEventHandler("Handler3"));
Task.Factory.StartNew(() => eventProcessor1.Run());
Task.Factory.StartNew(() => eventProcessor2.Run());
Task.Factory.StartNew(() => eventProcessor3.Run());
...
eventProcessor1.Halt();
eventProcessor2.Halt();
eventProcessor3.Halt();
...
P1
C1
C2
C3
Barrier
Barrier

37. DIAMOND: 1P – 3C

38. LMAX ARCHITECTURE

39. LMAX ARCHITECTURE

40. LMAX ARCHITECTURE

41. LMAX ARCHITECTURE
 Journaler
 Store all the events in a durable form
 Replicator
 Use IP multicasting to sync with slave node

42. REFERENCE
42

43. REFERENCE
 The LMAX Architecture
 http://martinfowler.com/articles/lmax.html
 Compare-and-swap - Wikipedia, the free
encyclopedia
 https://en.wikipedia.org/wiki/Compare-and-swap
 Memory barrier - Wikipedia, the free encyclopedia
 https://en.wikipedia.org/wiki/Memory_barrier
43

44. REFERENCE
 Circular buffer - Wikipedia, the free encyclopedia
 https://en.wikipedia.org/wiki/Circular_buffer
 并发框架Disruptor译文 | 并发编程网 - ifeve.com
 http://ifeve.com/disruptor/
 [C#][VB.NET].NET 4.0 Barrier Class | Level Up - 點
部落
 https://dotblogs.com.tw/larrynung/archive/2009/08/22/10
182.aspx?fid=9457
44

45. Q&A
45

46. QUESTION & ANSWER
46