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https://github.com/marusama/semaphore
Fast resizable golang semaphore primitive
https://github.com/marusama/semaphore
go golang mutex primitive semaphore semaphore-pattern synchronization
Last synced: 10 days ago
JSON representation
Fast resizable golang semaphore primitive
- Host: GitHub
- URL: https://github.com/marusama/semaphore
- Owner: marusama
- License: mit
- Created: 2017-11-22T14:00:58.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2021-03-28T09:27:47.000Z (over 3 years ago)
- Last Synced: 2024-08-20T17:20:36.696Z (3 months ago)
- Topics: go, golang, mutex, primitive, semaphore, semaphore-pattern, synchronization
- Language: Go
- Homepage:
- Size: 76.2 KB
- Stars: 170
- Watchers: 3
- Forks: 9
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
- awesome-go - semaphore - Fast resizable semaphore implementation based on CAS (faster than channel-based semaphore implementations). (Goroutines / Search and Analytic Databases)
- awesome-go - semaphore - Fast resizable golang semaphore - ★ 44 (Goroutines)
- awesome-go-extra - semaphore - 11-22T14:00:58Z|2021-03-28T09:27:47Z| (Goroutines / Advanced Console UIs)
README
semaphore
=========
[](https://github.com/avelino/awesome-go#goroutines)
[](https://travis-ci.org/marusama/semaphore)
[](https://goreportcard.com/report/github.com/marusama/semaphore)
[](https://coveralls.io/github/marusama/semaphore?branch=master)
[](https://godoc.org/github.com/marusama/semaphore)
[](LICENSE)
Fast resizable golang semaphore based on CAS
* allows weighted acquire/release;
* supports cancellation via context;
* allows change semaphore limit after creation;
* faster than channel based semaphores.
### Usage
Initiate
```go
import "github.com/marusama/semaphore/v2"
...
sem := semaphore.New(5) // new semaphore with limit = 5
```
Acquire
```go
sem.Acquire(ctx, n) // acquire n with context
sem.TryAcquire(n) // try acquire n without blocking
...
ctx := context.WithTimeout(context.Background(), time.Second)
sem.Acquire(ctx, n) // acquire n with timeout
```
Release
```go
sem.Release(n) // release n
```
Change semaphore limit
```go
sem.SetLimit(new_limit) // set new semaphore limit
```
### Some benchmarks
Run on MacBook Pro (2017) with 3,1GHz Core i5 cpu and 8GB DDR3 ram, macOS High Sierra, go version go1.11.4 darwin/amd64:
```text
// this semaphore:
BenchmarkSemaphore_Acquire_Release_under_limit_simple-4 20000000 98.6 ns/op 96 B/op 1 allocs/op
BenchmarkSemaphore_Acquire_Release_under_limit-4 1000000 1593 ns/op 960 B/op 10 allocs/op
BenchmarkSemaphore_Acquire_Release_over_limit-4 100000 20760 ns/op 9600 B/op 100 allocs/op
// some other implementations:
// golang.org/x/sync/semaphore:
BenchmarkXSyncSemaphore_Acquire_Release_under_limit_simple-4 50000000 34.9 ns/op 0 B/op 0 allocs/op
BenchmarkXSyncSemaphore_Acquire_Release_under_limit-4 1000000 1103 ns/op 0 B/op 0 allocs/op
BenchmarkXSyncSemaphore_Acquire_Release_over_limit-4 30000 65927 ns/op 15985 B/op 299 allocs/op
// github.com/abiosoft/semaphore:
BenchmarkAbiosoftSemaphore_Acquire_Release_under_limit_simple-4 10000000 208 ns/op 0 B/op 0 allocs/op
BenchmarkAbiosoftSemaphore_Acquire_Release_under_limit-4 500000 3147 ns/op 0 B/op 0 allocs/op
BenchmarkAbiosoftSemaphore_Acquire_Release_over_limit-4 50000 37148 ns/op 0 B/op 0 allocs/op
// github.com/dropbox/godropbox
BenchmarkDropboxBoundedSemaphore_Acquire_Release_under_limit_simple-4 20000000 75.9 ns/op 0 B/op 0 allocs/op
BenchmarkDropboxBoundedSemaphore_Acquire_Release_under_limit-4 2000000 629 ns/op 0 B/op 0 allocs/op
BenchmarkDropboxBoundedSemaphore_Acquire_Release_over_limit-4 200000 27308 ns/op 0 B/op 0 allocs/op
BenchmarkDropboxUnboundedSemaphore_Acquire_Release_under_limit_simple-4 50000000 39.7 ns/op 0 B/op 0 allocs/op
BenchmarkDropboxUnboundedSemaphore_Acquire_Release_under_limit-4 1000000 1170 ns/op 0 B/op 0 allocs/op
BenchmarkDropboxUnboundedSemaphore_Acquire_Release_over_limit-4 100000 21013 ns/op 0 B/op 0 allocs/op
// github.com/kamilsk/semaphore
BenchmarkKamilskSemaphore_Acquire_Release_under_limit_simple-4 20000000 110 ns/op 16 B/op 1 allocs/op
BenchmarkKamilskSemaphore_Acquire_Release_under_limit-4 1000000 1520 ns/op 160 B/op 10 allocs/op
BenchmarkKamilskSemaphore_Acquire_Release_over_limit-4 50000 42693 ns/op 1600 B/op 100 allocs/op
// github.com/pivotal-golang/semaphore
BenchmarkPivotalGolangSemaphore_Acquire_Release_under_limit_simple-4 3000000 558 ns/op 136 B/op 2 allocs/op
BenchmarkPivotalGolangSemaphore_Acquire_Release_under_limit-4 200000 9530 ns/op 1280 B/op 20 allocs/op
BenchmarkPivotalGolangSemaphore_Acquire_Release_over_limit-4 10000 111264 ns/op 12801 B/op 200 allocs/op
```
You can rerun these benchmarks, just checkout `benchmarks` branch and run `go test -bench=. -benchmem ./bench/...`