| # xxhash |
| |
| [](https://pkg.go.dev/github.com/cespare/xxhash/v2) |
| [](https://github.com/cespare/xxhash/actions/workflows/test.yml) |
| |
| xxhash is a Go implementation of the 64-bit |
| [xxHash](http://cyan4973.github.io/xxHash/) algorithm, XXH64. This is a |
| high-quality hashing algorithm that is much faster than anything in the Go |
| standard library. |
| |
| This package provides a straightforward API: |
| |
| ``` |
| func Sum64(b []byte) uint64 |
| func Sum64String(s string) uint64 |
| type Digest struct{ ... } |
| func New() *Digest |
| ``` |
| |
| The `Digest` type implements hash.Hash64. Its key methods are: |
| |
| ``` |
| func (*Digest) Write([]byte) (int, error) |
| func (*Digest) WriteString(string) (int, error) |
| func (*Digest) Sum64() uint64 |
| ``` |
| |
| The package is written with optimized pure Go and also contains an even faster |
| assembly implementation for amd64. If desired, the `purego` build tag opts into |
| using the Go code even on amd64. |
| |
| ## Compatibility |
| |
| This package is in a module and the latest code is in version 2 of the module. |
| You need a version of Go with at least "minimal module compatibility" to use |
| github.com/cespare/xxhash/v2: |
| |
| * 1.9.7+ for Go 1.9 |
| * 1.10.3+ for Go 1.10 |
| * Go 1.11 or later |
| |
| I recommend using the latest release of Go. |
| |
| ## Benchmarks |
| |
| Here are some quick benchmarks comparing the pure-Go and assembly |
| implementations of Sum64. |
| |
| | input size | purego | asm | |
| | --- | --- | --- | |
| | 4 B | 1052.65 MB/s | 1278.48 MB/s | |
| | 100 B | 6816.82 MB/s | 7881.09 MB/s | |
| | 4 KB | 11924.07 MB/s | 17323.63 MB/s | |
| | 10 MB | 11205.21 MB/s | 15484.85 MB/s | |
| |
| These numbers were generated on Ubuntu 18.04 with an Intel i7-8700K CPU using |
| the following commands under Go 1.17: |
| |
| ``` |
| go test -tags purego -benchtime 10s -bench 'Sum64$' |
| go test -benchtime 10s -bench 'Sum64$' |
| ``` |
| |
| ## Projects using this package |
| |
| - [InfluxDB](https://github.com/influxdata/influxdb) |
| - [Prometheus](https://github.com/prometheus/prometheus) |
| - [VictoriaMetrics](https://github.com/VictoriaMetrics/VictoriaMetrics) |
| - [FreeCache](https://github.com/coocood/freecache) |
| - [FastCache](https://github.com/VictoriaMetrics/fastcache) |
