Clone this repo:
  1. 1a548c8 Fix skipped test case by Caleb Spare · 5 months ago master
  2. fd5c34b Remove useless assignment by Caleb Spare · 5 months ago
  3. a7909af Allow Sum64String and (*Digest).WriteString to be inlined by Caleb Spare · 5 months ago sum64string-inline
  4. e0ea1e3 Rewrite benchmarks not to use indirect calls by Caleb Spare · 5 months ago
  5. 9160c38 Add FastCache to the Projects using this package by Gerasimos (Makis) Maropoulos · 5 months ago


GoDoc Build Status

xxhash is a Go implementation of the 64-bit 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

This implementation provides a fast pure-Go implementation and an even faster assembly implementation for amd64.


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

  • 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.


Here are some quick benchmarks comparing the pure-Go and assembly implementations of Sum64.

input sizepuregoasm
5 B979.66 MB/s1291.17 MB/s
100 B7475.26 MB/s7973.40 MB/s
4 KB17573.46 MB/s17602.65 MB/s
10 MB17131.46 MB/s17142.16 MB/s

These numbers were generated on Ubuntu 18.04 with an Intel i7-8700K CPU using the following commands under Go 1.11.2:

$ go test -tags purego -benchtime 10s -bench '/xxhash,direct,bytes'
$ go test -benchtime 10s -bench '/xxhash,direct,bytes'

Projects using this package