├── .github └── workflows │ └── go.yml ├── LICENSE ├── README.md ├── benchmark_test.go ├── go.mod ├── go.sum ├── ringbuffer.go └── ringbuffer_test.go /.github/workflows/go.yml: -------------------------------------------------------------------------------- 1 | # This workflow will build a golang project 2 | # For more information see: https://docs.github.com/en/actions/automating-builds-and-tests/building-and-testing-go 3 | 4 | name: Go 5 | 6 | on: 7 | push: 8 | branches: [ "master" ] 9 | pull_request: 10 | branches: [ "master" ] 11 | 12 | jobs: 13 | 14 | build: 15 | runs-on: ubuntu-latest 16 | steps: 17 | - uses: actions/checkout@v3 18 | 19 | - name: Set up Go 20 | uses: actions/setup-go@v4 21 | with: 22 | go-version: '1.20' 23 | 24 | - name: Build 25 | run: go build -v ./... 26 | 27 | - name: Test 28 | run: go test -v ./... 29 | -------------------------------------------------------------------------------- /LICENSE: -------------------------------------------------------------------------------- 1 | Apache License 2 | Version 2.0, January 2004 3 | http://www.apache.org/licenses/ 4 | 5 | TERMS AND CONDITIONS FOR USE, REPRODUCTION, AND DISTRIBUTION 6 | 7 | 1. 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The text should be enclosed in the appropriate 184 | comment syntax for the file format. We also recommend that a 185 | file or class name and description of purpose be included on the 186 | same "printed page" as the copyright notice for easier 187 | identification within third-party archives. 188 | 189 | Copyright [yyyy] [name of copyright owner] 190 | 191 | Licensed under the Apache License, Version 2.0 (the "License"); 192 | you may not use this file except in compliance with the License. 193 | You may obtain a copy of the License at 194 | 195 | http://www.apache.org/licenses/LICENSE-2.0 196 | 197 | Unless required by applicable law or agreed to in writing, software 198 | distributed under the License is distributed on an "AS IS" BASIS, 199 | WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 200 | See the License for the specific language governing permissions and 201 | limitations under the License. 202 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # LocklessGenericRingBuffer 2 | 3 | LocklessGenericRingBuffer is a single producer, multi reader lockless ring buffer utilizing the new generics available in 4 | `go 1.18+`. Instead of passing typeless `interface{}` or byte arrays we are able to pass serialized structs between go routines in a type safe manner. 5 | 6 | ### What is a lockless ringbuffer ? 7 | 8 | A ring buffer, also known as a circular buffer, is a fixed-size buffer that can be efficiently appended to and read from. This implementation allows for multiple goroutines to concurrently read and a single goroutine to write to the buffer without the need for locks, ensuring maximum throughput and minimal latency. 9 | 10 | 11 | ## Benefits 12 | 13 | - [x] Zero Heap Allocations 14 | - [x] Cache Friendly as underlying structures are continuous in memory 15 | - [x] Faster then channels for highly contended workloads (See Benchmarks) 16 | - [x] Zero Dependencies 17 | 18 | ## Requirements 19 | - `golang 1.18.x or above` 20 | 21 | ## Getting started 22 | 23 | **Note: writers and consumers are NOT thread safe, i.e. only use a consumer in a single go routine** 24 | 25 | ### Install 26 | 27 | ``` 28 | go get github.com/GavinClarke0/lockless-generic-ring-buffer 29 | ``` 30 | 31 | ### Create and Consume 32 | ```go 33 | var buffer, _ = CreateBuffer[int](16) // buffer size must be to the power 2 34 | 35 | messages := []int{1, 2, 3, 4, 5, 6, 7, 8, 9} 36 | consumer, _ := buffer.CreateConsumer() 37 | 38 | for _, value := range messages { 39 | buffer.Write(value) 40 | } 41 | 42 | for _, _ = range messages { 43 | _ = consumer.Get() 44 | } 45 | ``` 46 | 47 | ### Remove a Consumer 48 | ```go 49 | var consumer, _ = buffer.CreateConsumer() 50 | consumer.Remove() 51 | ``` 52 | 53 | ## Benchmarks 54 | 55 | ### Comparison against channels 56 | 57 | Benchmarks are ran on a **M1 Macbook Air (16gb ram)**. 58 | 59 | **Note: each benchmark does not include creation time of the consumers/channels.** 60 | 61 | ```sql 62 | BenchmarkConsumerSequentialReadWriteLarge-8 20 55602675 ns/op 0 B/op 0 allocs/op 63 | BenchmarkChannelsSequentialReadWriteLarge-8 8 133155344 ns/op 0 B/op 0 allocs/op 64 | BenchmarkConsumerSequentialReadWriteMedium-8 1063 1123298 ns/op 0 B/op 0 allocs/op 65 | BenchmarkChannelsSequentialReadWriteMedium-8 451 2650842 ns/op 0 B/op 0 allocs/op 66 | BenchmarkConsumerSequentialReadWriteSmall-8 99393 12099 ns/op 0 B/op 0 allocs/op 67 | BenchmarkChannelsSequentialReadWriteSmall-8 41755 28758 ns/op 0 B/op 0 allocs/op 68 | BenchmarkConsumerConcurrentReadWriteLarge-8 5 223985800 ns/op 345 B/op 2 allocs/op 69 | BenchmarkChannelsConcurrentReadWriteLarge-8 2 858931292 ns/op 144 B/op 2 allocs/op 70 | BenchmarkConsumerConcurrentReadWriteMedium-8 278 4554057 ns/op 217 B/op 2 allocs/op 71 | BenchmarkChannelsConcurrentReadWriteMedium-8 90 17578294 ns/op 169 B/op 2 allocs/op 72 | BenchmarkConsumerConcurrentReadWriteSmall-8 36378 33837 ns/op 96 B/op 2 allocs/op 73 | BenchmarkChannelsConcurrentReadWriteSmall-8 25004 47466 ns/op 97 B/op 2 allocs/op 74 | 75 | ``` 76 | 77 | In sequential benchmarks it is about `2x` the read write speed of channels. 78 | 79 | In concurrent benchmarks, where operations can block, it is about `2x` faster than the channel implementation. 80 | 81 | ## Testing 82 | 83 | To run current tests: `go test` 84 | 85 | To detect race conditions run with `go test -race`, which as of the latest commit (January 24, 2021) with the current test cases it 86 | passes. 87 | 88 | **Note** this does not mean it is race condition free. 89 | Additional tests, especially on creating and removing consumers in concurrent environments are needed. 90 | -------------------------------------------------------------------------------- /benchmark_test.go: -------------------------------------------------------------------------------- 1 | package locklessgenericringbuffer 2 | 3 | import ( 4 | "sync" 5 | "testing" 6 | ) 7 | 8 | const ( 9 | MessageCountLarge = 5000000 10 | MessageCountMedium = 100000 11 | MessageCountSmall = 1000 12 | ) 13 | 14 | func BenchmarkConsumerSequentialReadWriteLarge(b *testing.B) { 15 | for n := 0; n < b.N; n++ { 16 | ConsumerSequentialReadWrite(MessageCountLarge, b) 17 | } 18 | } 19 | 20 | func BenchmarkChannelsSequentialReadWriteLarge(b *testing.B) { 21 | for n := 0; n < b.N; n++ { 22 | ChannelsSequentialReadWrite(MessageCountLarge, b) 23 | } 24 | } 25 | 26 | func BenchmarkConsumerSequentialReadWriteMedium(b *testing.B) { 27 | for n := 0; n < b.N; n++ { 28 | ConsumerSequentialReadWrite(MessageCountMedium, b) 29 | } 30 | } 31 | 32 | func BenchmarkChannelsSequentialReadWriteMedium(b *testing.B) { 33 | for n := 0; n < b.N; n++ { 34 | ChannelsSequentialReadWrite(MessageCountMedium, b) 35 | } 36 | } 37 | 38 | func BenchmarkConsumerSequentialReadWriteSmall(b *testing.B) { 39 | for n := 0; n < b.N; n++ { 40 | ConsumerSequentialReadWrite(MessageCountSmall, b) 41 | } 42 | } 43 | 44 | func BenchmarkChannelsSequentialReadWriteSmall(b *testing.B) { 45 | for n := 0; n < b.N; n++ { 46 | ChannelsSequentialReadWrite(MessageCountSmall, b) 47 | } 48 | } 49 | 50 | func ConsumerSequentialReadWrite(n int, b *testing.B) { 51 | 52 | b.StopTimer() 53 | var buffer, _ = CreateBuffer[int](BufferSizeStandard, 10) 54 | consumer, _ := buffer.CreateConsumer() 55 | b.StartTimer() 56 | 57 | for i := 0; i < n; i++ { 58 | buffer.Write(i) 59 | consumer.Get() 60 | } 61 | } 62 | 63 | func ChannelsSequentialReadWrite(n int, b *testing.B) { 64 | 65 | b.StopTimer() 66 | var buffer = make(chan int, BufferSizeStandard) 67 | b.StartTimer() 68 | 69 | for i := 0; i < n; i++ { 70 | buffer <- i 71 | <-buffer 72 | } 73 | } 74 | 75 | /* 76 | General Benchmark to compare concurrent reading from channels vrs the ring buffer. 77 | Note there is heavy over head for syncing the routines in both and is not accurate beyond a general comparison. 78 | */ 79 | func BenchmarkConsumerConcurrentReadWriteLarge(b *testing.B) { 80 | for n := 0; n < b.N; n++ { 81 | ConsumerConcurrentReadWrite(MessageCountLarge, b) 82 | } 83 | } 84 | 85 | func BenchmarkChannelsConcurrentReadWriteLarge(b *testing.B) { 86 | for n := 0; n < b.N; n++ { 87 | ChannelsConcurrentReadWrite(MessageCountLarge, b) 88 | } 89 | } 90 | 91 | func BenchmarkConsumerConcurrentReadWriteMedium(b *testing.B) { 92 | for n := 0; n < b.N; n++ { 93 | ConsumerConcurrentReadWrite(MessageCountMedium, b) 94 | } 95 | } 96 | 97 | func BenchmarkChannelsConcurrentReadWriteMedium(b *testing.B) { 98 | for n := 0; n < b.N; n++ { 99 | ChannelsConcurrentReadWrite(MessageCountMedium, b) 100 | } 101 | } 102 | func BenchmarkConsumerConcurrentReadWriteSmall(b *testing.B) { 103 | for n := 0; n < b.N; n++ { 104 | ConsumerConcurrentReadWrite(MessageCountSmall, b) 105 | } 106 | } 107 | 108 | func BenchmarkChannelsConcurrentReadWriteSmall(b *testing.B) { 109 | for n := 0; n < b.N; n++ { 110 | ChannelsConcurrentReadWrite(MessageCountSmall, b) 111 | } 112 | } 113 | 114 | func ConsumerConcurrentReadWrite(n int, b *testing.B) { 115 | 116 | b.StopTimer() 117 | var buffer, _ = CreateBuffer[int](BufferSizeStandard, 10) 118 | 119 | var wg sync.WaitGroup 120 | messages := []int{} 121 | 122 | for i := 0; i < n; i++ { 123 | messages = append(messages, i) 124 | } 125 | 126 | consumer, _ := buffer.CreateConsumer() 127 | b.StartTimer() 128 | 129 | wg.Add(1) 130 | go func() { 131 | defer wg.Done() 132 | for _, value := range messages { 133 | buffer.Write(value) 134 | } 135 | }() 136 | 137 | wg.Add(1) 138 | go func() { 139 | i := -1 140 | defer wg.Done() 141 | for _, _ = range messages { 142 | j := consumer.Get() 143 | if j != i+1 { 144 | panic("data is inconsistent") 145 | } 146 | i = j 147 | } 148 | }() 149 | wg.Wait() 150 | } 151 | 152 | func ChannelsConcurrentReadWrite(n int, b *testing.B) { 153 | 154 | b.StopTimer() 155 | var wg sync.WaitGroup 156 | messages := []int{} 157 | 158 | for i := 0; i < n; i++ { 159 | messages = append(messages, i) 160 | } 161 | 162 | var buffer = make(chan int, BufferSizeStandard) 163 | b.StartTimer() 164 | 165 | wg.Add(1) 166 | go func() { 167 | defer wg.Done() 168 | for _, value := range messages { 169 | buffer <- value 170 | } 171 | }() 172 | 173 | wg.Add(1) 174 | go func() { 175 | i := -1 176 | defer wg.Done() 177 | for _, _ = range messages { 178 | j := <-buffer 179 | if j != i+1 { 180 | panic("data is inconsistent") 181 | } 182 | i = j 183 | } 184 | }() 185 | wg.Wait() 186 | } 187 | -------------------------------------------------------------------------------- /go.mod: -------------------------------------------------------------------------------- 1 | module github.com/GavinClarke0/lockless-generic-ring-buffer 2 | 3 | go 1.18 4 | -------------------------------------------------------------------------------- /go.sum: -------------------------------------------------------------------------------- https://raw.githubusercontent.com/GavinClarke0/lockless-generic-ring-buffer/f1bd69b6f13ad39f3b8c1465d543ba1917641de6/go.sum -------------------------------------------------------------------------------- /ringbuffer.go: -------------------------------------------------------------------------------- 1 | package locklessgenericringbuffer 2 | 3 | import ( 4 | "errors" 5 | "runtime" 6 | "sync/atomic" 7 | ) 8 | 9 | var ( 10 | MaxConsumerError = errors.New("max amount of consumers reached cannot create any more") 11 | InvalidBufferSize = errors.New("buffer must be of size 2^n") 12 | ) 13 | 14 | type RingBuffer[T any] struct { 15 | length uint32 16 | bitWiseLength uint32 17 | headIndex uint32 // next position to write 18 | nextReaderIndex uint32 19 | maxReaders int 20 | buffer []T 21 | readerIndexes []uint32 22 | readerActiveFlags []uint32 23 | } 24 | 25 | type Consumer[T any] struct { 26 | ring *RingBuffer[T] 27 | id uint32 28 | } 29 | 30 | func CreateBuffer[T any](size uint32, maxReaders uint32) (RingBuffer[T], error) { 31 | 32 | if size&(size-1) != 0 { 33 | return RingBuffer[T]{}, InvalidBufferSize 34 | } 35 | 36 | return RingBuffer[T]{ 37 | buffer: make([]T, size, size), 38 | length: size, 39 | bitWiseLength: size - 1, 40 | headIndex: 0, 41 | nextReaderIndex: 0, 42 | maxReaders: int(maxReaders), 43 | readerIndexes: make([]uint32, maxReaders), 44 | readerActiveFlags: make([]uint32, maxReaders), 45 | }, nil 46 | } 47 | 48 | /* 49 | CreateConsumer 50 | 51 | Create a consumer by assigning it the id of the first empty position in the consumerPosition array. Consumer status is track 52 | via a flag array with 0 meaning empty, 1 in use and 2 as an intermittent state of being created 53 | */ 54 | func (buffer *RingBuffer[T]) CreateConsumer() (Consumer[T], error) { 55 | 56 | for readerIndex, _ := range buffer.readerActiveFlags { 57 | if atomic.CompareAndSwapUint32(&buffer.readerActiveFlags[readerIndex], 0, 2) { 58 | 59 | // as read state is set to 2, we can afford to non atomically set readIndex, no writer will access it 60 | buffer.readerIndexes[readerIndex] = atomic.LoadUint32(&buffer.headIndex) 61 | atomic.StoreUint32(&buffer.readerActiveFlags[readerIndex], 1) 62 | 63 | // case where reader has the current maximum id, and it is needed to be incremented 64 | atomic.CompareAndSwapUint32(&buffer.nextReaderIndex, uint32(readerIndex), uint32(readerIndex)+1) 65 | 66 | return Consumer[T]{ 67 | id: uint32(readerIndex), 68 | ring: buffer, 69 | }, nil 70 | } 71 | } 72 | 73 | return Consumer[T]{}, MaxConsumerError 74 | } 75 | 76 | func (buffer *RingBuffer[T]) removeConsumer(readerId uint32) { 77 | atomic.StoreUint32(&buffer.readerActiveFlags[readerId], 0) 78 | atomic.CompareAndSwapUint32(&buffer.nextReaderIndex, readerId-1, buffer.nextReaderIndex-1) 79 | } 80 | 81 | func (consumer *Consumer[T]) Remove() { 82 | consumer.ring.removeConsumer(consumer.id) 83 | } 84 | 85 | func (consumer *Consumer[T]) Get() T { 86 | return consumer.ring.readIndex(consumer.id) 87 | } 88 | 89 | func (buffer *RingBuffer[T]) Write(value T) { 90 | 91 | var offset uint32 92 | var i uint32 93 | /* 94 | We are blocking until the all at least one space is available in the buffer to attemptWrite. 95 | 96 | As overflow properties of uint32 are utilized to ensure slice index boundaries are adhered too we add the length 97 | of buffer to current reader's position allowing us to determine the least read reader. 98 | 99 | For example: buffer of size 2 100 | 101 | uint8 head = 1 102 | uint8 tail = 255 103 | tail + 2 => 1 with overflow, same as buffer 104 | */ 105 | 106 | attemptWrite: 107 | nextReaderIndex := atomic.LoadUint32(&buffer.nextReaderIndex) 108 | 109 | for i = 0; i < nextReaderIndex; i++ { 110 | if atomic.LoadUint32(&buffer.readerActiveFlags[i]) == 1 { 111 | offset = atomic.LoadUint32(&buffer.readerIndexes[i]) + buffer.length 112 | 113 | // only true if the offset between at least one reader and the writer is equal to the size of the buffer 114 | if offset == buffer.headIndex { 115 | runtime.Gosched() 116 | goto attemptWrite 117 | } 118 | } 119 | } 120 | 121 | nextIndex := buffer.headIndex + 1 122 | buffer.buffer[nextIndex&buffer.bitWiseLength] = value 123 | atomic.StoreUint32(&buffer.headIndex, nextIndex) 124 | return 125 | 126 | } 127 | 128 | func (buffer *RingBuffer[T]) readIndex(readerIndex uint32) T { 129 | 130 | newIndex := buffer.readerIndexes[readerIndex] + 1 131 | // yield until work is available 132 | for newIndex > atomic.LoadUint32(&buffer.headIndex) { 133 | runtime.Gosched() 134 | } 135 | 136 | value := buffer.buffer[newIndex&buffer.bitWiseLength] 137 | atomic.AddUint32(&buffer.readerIndexes[readerIndex], 1) 138 | return value 139 | } 140 | -------------------------------------------------------------------------------- /ringbuffer_test.go: -------------------------------------------------------------------------------- 1 | package locklessgenericringbuffer 2 | 3 | import ( 4 | "crypto/rand" 5 | "sync" 6 | "testing" 7 | "time" 8 | ) 9 | 10 | const ( 11 | BufferSizeStandard = 256 12 | BufferSizeSmall = 16 13 | BufferSizeTiny = 2 14 | ) 15 | 16 | func TestGetsAreSequentiallyOrdered(t *testing.T) { 17 | 18 | //ring := make([]int, 10, 10) 19 | 20 | var buffer, _ = CreateBuffer[int](BufferSizeSmall, 10) 21 | 22 | messages := []int{1, 2, 3, 4, 5, 6, 7, 8, 9} 23 | consumer, _ := buffer.CreateConsumer() 24 | 25 | for _, value := range messages { 26 | buffer.Write(value) 27 | } 28 | 29 | for i, _ := range messages { 30 | value := consumer.Get() 31 | 32 | if value != messages[i] { 33 | t.FailNow() 34 | } 35 | } 36 | } 37 | 38 | // test adding a consumer mid work 39 | func TestNewConsumerReadsFromCurrentWritePosition(t *testing.T) { 40 | 41 | var buffer, _ = CreateBuffer[int](BufferSizeStandard, 10) 42 | 43 | messages := []int{1, 2, 3, 4, 5, 6, 7, 8, 9} 44 | 45 | consumer1, _ := buffer.CreateConsumer() 46 | 47 | for _, value := range messages[:5] { 48 | buffer.Write(value) 49 | } 50 | 51 | consumer2, _ := buffer.CreateConsumer() 52 | 53 | for _, value := range messages[5:] { 54 | buffer.Write(value) 55 | } 56 | 57 | for _, value := range messages { 58 | 59 | getValue := consumer1.Get() 60 | 61 | if getValue != value { 62 | t.Fail() 63 | } 64 | } 65 | 66 | // test it reads froms 67 | for _, value := range messages[5:] { 68 | getValue := consumer2.Get() 69 | 70 | if getValue != value { 71 | t.Fail() 72 | } 73 | } 74 | 75 | } 76 | 77 | // test adding a consumer mid work 78 | func TestRemovingConsumerDoesNotBlockNewWrites(t *testing.T) { 79 | 80 | var buffer, _ = CreateBuffer[int](BufferSizeStandard, 10) 81 | 82 | messages := []int{1, 2, 3, 4, 5, 6, 7, 8, 9} 83 | 84 | consumer1, _ := buffer.CreateConsumer() 85 | consumer2, _ := buffer.CreateConsumer() 86 | 87 | for _, value := range messages[:5] { 88 | buffer.Write(value) 89 | } 90 | 91 | consumer2.Remove() 92 | 93 | for _, value := range messages[5:] { 94 | buffer.Write(value) 95 | } 96 | 97 | for _, value := range messages { 98 | 99 | getValue := consumer1.Get() 100 | 101 | if getValue != value { 102 | t.Fail() 103 | } 104 | } 105 | 106 | if buffer.readerActiveFlags[1] != 0 { 107 | t.Fail() 108 | } 109 | } 110 | 111 | // Test order is still preserved with simultaneous reading writing 112 | func TestConcurrentGetsAreSequentiallyOrdered(t *testing.T) { 113 | 114 | var buffer, _ = CreateBuffer[int](BufferSizeStandard, 10) 115 | 116 | var wg sync.WaitGroup 117 | messages := []int{} 118 | 119 | for i := 0; i < 100000; i++ { 120 | messages = append(messages, i) 121 | } 122 | 123 | consumer, _ := buffer.CreateConsumer() 124 | 125 | wg.Add(1) 126 | go func() { 127 | defer wg.Done() 128 | for _, value := range messages { 129 | buffer.Write(value) 130 | } 131 | }() 132 | 133 | wg.Add(1) 134 | go func() { 135 | defer wg.Done() 136 | for _, value := range messages { 137 | j := consumer.Get() 138 | if j != value { 139 | t.Fail() 140 | } 141 | } 142 | }() 143 | wg.Wait() 144 | } 145 | 146 | // Test order is still preserved with simultaneous reading writing 147 | func TestConcurrentGetsAreSequentiallyOrderedMinibuffer(t *testing.T) { 148 | 149 | var buffer, _ = CreateBuffer[int](BufferSizeTiny, 10) 150 | 151 | var wg sync.WaitGroup 152 | messages := []int{} 153 | 154 | for i := 0; i < 100000; i++ { 155 | messages = append(messages, i) 156 | } 157 | 158 | consumer, _ := buffer.CreateConsumer() 159 | 160 | wg.Add(1) 161 | go func() { 162 | defer wg.Done() 163 | for _, value := range messages { 164 | buffer.Write(value) 165 | } 166 | }() 167 | 168 | wg.Add(1) 169 | go func() { 170 | defer wg.Done() 171 | for _, value := range messages { 172 | j := consumer.Get() 173 | if j != value { 174 | t.Fail() 175 | } 176 | } 177 | }() 178 | wg.Wait() 179 | } 180 | 181 | func TestConcurrentStringsGetsAreSequentiallyOrderedWithMultiConsumer(t *testing.T) { 182 | 183 | var buffer, _ = CreateBuffer[string](BufferSizeSmall, 10) 184 | 185 | var wg sync.WaitGroup 186 | messages := []string{} 187 | 188 | for i := 0; i < 100000; i++ { 189 | token := make([]byte, 16) 190 | rand.Read(token) 191 | messages = append(messages, string(token)) 192 | } 193 | 194 | consumer1, _ := buffer.CreateConsumer() 195 | consumer2, _ := buffer.CreateConsumer() 196 | consumer3, _ := buffer.CreateConsumer() 197 | 198 | wg.Add(1) 199 | go func() { 200 | defer wg.Done() 201 | for _, value := range messages { 202 | buffer.Write(value) 203 | } 204 | }() 205 | 206 | wg.Add(1) 207 | go func() { 208 | defer wg.Done() 209 | for _, value := range messages { 210 | j := consumer1.Get() 211 | if j != value { 212 | t.Fail() 213 | } 214 | } 215 | }() 216 | 217 | wg.Add(1) 218 | go func() { 219 | defer wg.Done() 220 | for _, value := range messages { 221 | j := consumer2.Get() 222 | if j != value { 223 | t.Fail() 224 | } 225 | } 226 | }() 227 | 228 | wg.Add(1) 229 | go func() { 230 | defer wg.Done() 231 | for _, value := range messages { 232 | j := consumer3.Get() 233 | if j != value { 234 | t.Fail() 235 | } 236 | } 237 | }() 238 | wg.Wait() 239 | } 240 | 241 | // Test all values are read in order 242 | func TestConcurrentGetsAreSequentiallyOrderedWithMultiConsumer(t *testing.T) { 243 | 244 | var buffer, _ = CreateBuffer[int](BufferSizeStandard, 10) 245 | 246 | var wg sync.WaitGroup 247 | messages := []int{} 248 | 249 | for i := 0; i < 1000000; i++ { 250 | messages = append(messages, i) 251 | } 252 | 253 | consumer1, _ := buffer.CreateConsumer() 254 | consumer2, _ := buffer.CreateConsumer() 255 | consumer3, _ := buffer.CreateConsumer() 256 | 257 | wg.Add(1) 258 | go func() { 259 | defer wg.Done() 260 | for _, value := range messages { 261 | buffer.Write(value) 262 | } 263 | }() 264 | 265 | wg.Add(1) 266 | go func() { 267 | defer wg.Done() 268 | for _, value := range messages { 269 | j := consumer1.Get() 270 | if j != value { 271 | t.Fail() 272 | } 273 | } 274 | }() 275 | 276 | wg.Add(1) 277 | go func() { 278 | defer wg.Done() 279 | for _, value := range messages { 280 | j := consumer2.Get() 281 | if j != value { 282 | t.Fail() 283 | } 284 | } 285 | }() 286 | 287 | wg.Add(1) 288 | go func() { 289 | defer wg.Done() 290 | for _, value := range messages { 291 | j := consumer3.Get() 292 | if j != value { 293 | t.Fail() 294 | } 295 | } 296 | }() 297 | wg.Wait() 298 | } 299 | 300 | // Test all values are read in order 301 | func TestConcurrentAddRemoveConsumerDoesNotBlockWrites(t *testing.T) { 302 | 303 | var buffer, _ = CreateBuffer[int](BufferSizeStandard, 10) 304 | 305 | var wg sync.WaitGroup 306 | messages := []int{} 307 | 308 | for i := 0; i < 10000; i++ { 309 | messages = append(messages, i) 310 | } 311 | 312 | consumer1, _ := buffer.CreateConsumer() 313 | failIfDeadLock(t) 314 | 315 | wg.Add(1) 316 | go func() { 317 | defer wg.Done() 318 | for _, value := range messages { 319 | buffer.Write(value) 320 | } 321 | }() 322 | 323 | wg.Add(1) 324 | go func() { 325 | defer wg.Done() 326 | for _, value := range messages { 327 | j := consumer1.Get() 328 | if j != value { 329 | t.Fail() 330 | } 331 | } 332 | }() 333 | 334 | wg.Add(1) 335 | go func() { 336 | consumer2, _ := buffer.CreateConsumer() 337 | defer wg.Done() 338 | for _, _ = range messages[:500] { 339 | consumer2.Get() 340 | } 341 | 342 | consumer2.Remove() 343 | }() 344 | 345 | wg.Wait() 346 | } 347 | 348 | func failIfDeadLock(t *testing.T) { 349 | // fail if routine is blocking 350 | go time.AfterFunc(1*time.Second, func() { 351 | t.FailNow() 352 | }) 353 | } 354 | --------------------------------------------------------------------------------