README.md

DataflowChannel

A lock-free library for high-performance implementations of the producers\consumers data structures

OPOC - One Producer One Consumer

This channel to use only two threads at the same time. At the core a cycle buffer that implements a producer-consumer pattern. Wait-Free implementation without any CAS operations.

Performance:

Method	Mean	Error	StdDev	Min	Max	Op/s
Write	4.579 ns	0.3328 ns	0.0515 ns	4.529 ns	4.651 ns	218,410,951.1
Read	4.943 ns	0.1997 ns	0.0519 ns	4.873 ns	4.991 ns	202,290,061.0
ReadWrite	2.514 ns	0.1986 ns	0.0307 ns	2.470 ns	2.537 ns	397,820,105.0

MPOC no order - Multiple Producers One Consumer

Producers use a spinlock for an initialization thread only once at a time. All read-write operations fully lock-free\wait-free. No order means that read order is not equal to write order.

Bench read

Method	Threads	Mean	Error	StdDev	Min	Max	Op/s	Op/s total
Read	1	5.486 ns	0.5605 ns	0.0867 ns	5.383 ns	5.576 ns	182,277,205.5	182,277,205.50
Read	1	5.579 ns	1.0285 ns	0.1592 ns	5.368 ns	5.706 ns	179,246,162.3	179,246,162.30
Read	1	5.534 ns	0.5522 ns	0.0855 ns	5.436 ns	5.639 ns	180,693,096.3	180,693,096.30
Read	1	5.516 ns	0.5674 ns	0.1474 ns	5.339 ns	5.652 ns	181,305,252.8	181,305,252.80

Bench only writers:

Method	Threads	Mean	Error	StdDev	Min	Max	Op/s	Op/s total
Write	1	10.81 ns	3.655 ns	0.949 ns	9.628 ns	11.88 ns	92,503,720.5	92,503,720.50
Write	2	11.94 ns	2.431 ns	0.631 ns	11.234 ns	12.56 ns	83,753,388.7	167,506,777.40
Write	4	12.06 ns	0.702 ns	0.182 ns	11.827 ns	12.30 ns	82,945,042.7	331,780,170.80
Write	8	15.11 ns	0.432 ns	0.112 ns	14.985 ns	15.23 ns	66,184,357.4	529,474,859.20

Bench writers with one reader thread.

The consumer thread does operations all the time until the producers write everything down.

Method	Threads	Mean	Error	StdDev	Min	Max	Op/s	Op/s total
WriteWithReader	1	13.51 ns	10.501 ns	2.727 ns	11.31 ns	17.91 ns	74,023,925.3	74,023,925.30
WriteWithReader	2	12.07 ns	6.205 ns	0.960 ns	10.86 ns	13.04 ns	82,876,339.4	165,752,678.80
WriteWithReader	4	14.51 ns	3.133 ns	0.814 ns	13.85 ns	15.80 ns	68,905,927.4	275,623,709.60
WriteWithReader	8	17.50 ns	5.333 ns	1.385 ns	16.12 ns	19.48 ns	57,134,765.9	457,078,127.20

MPOC - Multiple Producers One Consumer

Coming soon

OPMC - One Producer Multiple Consumer

Coming soon

MPMC - Multiple Producer Multiple Consumer

Coming soon

Usage example

        static void Sample()
        {
            var producers = 8;
            var consumers = 1;
            var threads = producers + consumers;
            var ready = 0;
            var count = 100_000_000;
            var sw = Stopwatch.StartNew();

            // Attention: No more than one consumer and one producer
            //var channel = new ChannelOPOC<int>();
            
            // Attention: No more than one consumer
            var channel = new ChannelMPOCnoOrder<int>();
            
            // Run producers
            for (var n = 0; n < producers; n++)
            {
                Task.Factory.StartNew(() =>
                {
                    Interlocked.Add(ref ready, 1);

                    while (Volatile.Read(ref ready) < threads)
                    {
                    }

                    var start = sw.ElapsedMilliseconds;

                    for (int i = 0; i < count; i++)
                    {
                        channel.Write(i);
                    }

                    channel.Write(-1);

                    Console.WriteLine($"Producer time:{sw.ElapsedMilliseconds - start}, thread:{Thread.CurrentThread.ManagedThreadId}");

                }, CancellationToken.None, TaskCreationOptions.LongRunning, TaskScheduler.Default);
            }

            // Run consumers
            for (var n = 0; n < consumers; n++)
            {
                Task.Factory.StartNew(() =>
                {
                    Interlocked.Add(ref ready, 1);

                    while (Volatile.Read(ref ready) < threads)
                    {
                    }

                    var sum   = 0;
                    var empty = 0;
                    var exit  = 0;
                    var start = sw.ElapsedMilliseconds;

                    while (true)
                    {
                        if (channel.TryRead(out var num))
                        {
                            if (num == -1)
                            {
                                exit++;

                                if (exit == producers)
                                {
                                    break;
                                }

                                continue;
                            }

                            sum++;
                        }
                        else
                        {
                            empty++;
                        }
                    }

                    Console.WriteLine($"Consumer time:{sw.ElapsedMilliseconds - start}, thread:{Thread.CurrentThread.ManagedThreadId}, sum:{sum}, empty reads:{empty}");

                }, CancellationToken.None, TaskCreationOptions.LongRunning, TaskScheduler.Default);
            }
        }