mirror of
https://github.com/VictoriaMetrics/VictoriaMetrics.git
synced 2024-12-23 08:56:31 +01:00
77 lines
2.8 KiB
Markdown
77 lines
2.8 KiB
Markdown
|
[](https://travis-ci.org/valyala/fastrand)
|
||
|
|
[](http://godoc.org/github.com/valyala/fastrand)
|
||
|
|
[](https://goreportcard.com/report/github.com/valyala/fastrand)
|
||
|
|
|
||
|
|
|
||
|
|
# fastrand
|
||
|
|
|
||
|
|
Fast pseudorandom number generator.
|
||
|
|
|
||
|
|
|
||
|
|
# Features
|
||
|
|
|
||
|
|
- Optimized for speed.
|
||
|
|
- Performance scales on multiple CPUs.
|
||
|
|
|
||
|
|
# How does it work?
|
||
|
|
|
||
|
|
It abuses [sync.Pool](https://golang.org/pkg/sync/#Pool) for maintaining
|
||
|
|
"per-CPU" pseudorandom number generators.
|
||
|
|
|
||
|
|
TODO: firgure out how to use real per-CPU pseudorandom number generators.
|
||
|
|
|
||
|
|
|
||
|
|
# Benchmark results
|
||
|
|
|
||
|
|
|
||
|
|
```
|
||
|
|
$ GOMAXPROCS=1 go test -bench=. github.com/valyala/fastrand
|
||
|
|
goos: linux
|
||
|
|
goarch: amd64
|
||
|
|
pkg: github.com/valyala/fastrand
|
||
|
|
BenchmarkUint32n 50000000 29.7 ns/op
|
||
|
|
BenchmarkRNGUint32n 200000000 6.50 ns/op
|
||
|
|
BenchmarkRNGUint32nWithLock 100000000 21.5 ns/op
|
||
|
|
BenchmarkMathRandInt31n 50000000 31.8 ns/op
|
||
|
|
BenchmarkMathRandRNGInt31n 100000000 17.9 ns/op
|
||
|
|
BenchmarkMathRandRNGInt31nWithLock 50000000 30.2 ns/op
|
||
|
|
PASS
|
||
|
|
ok github.com/valyala/fastrand 10.634s
|
||
|
|
```
|
||
|
|
|
||
|
|
```
|
||
|
|
$ GOMAXPROCS=2 go test -bench=. github.com/valyala/fastrand
|
||
|
|
goos: linux
|
||
|
|
goarch: amd64
|
||
|
|
pkg: github.com/valyala/fastrand
|
||
|
|
BenchmarkUint32n-2 100000000 17.6 ns/op
|
||
|
|
BenchmarkRNGUint32n-2 500000000 3.36 ns/op
|
||
|
|
BenchmarkRNGUint32nWithLock-2 50000000 32.0 ns/op
|
||
|
|
BenchmarkMathRandInt31n-2 20000000 51.2 ns/op
|
||
|
|
BenchmarkMathRandRNGInt31n-2 100000000 11.0 ns/op
|
||
|
|
BenchmarkMathRandRNGInt31nWithLock-2 20000000 91.0 ns/op
|
||
|
|
PASS
|
||
|
|
ok github.com/valyala/fastrand 9.543s
|
||
|
|
```
|
||
|
|
|
||
|
|
```
|
||
|
|
$ GOMAXPROCS=4 go test -bench=. github.com/valyala/fastrand
|
||
|
|
goos: linux
|
||
|
|
goarch: amd64
|
||
|
|
pkg: github.com/valyala/fastrand
|
||
|
|
BenchmarkUint32n-4 100000000 14.2 ns/op
|
||
|
|
BenchmarkRNGUint32n-4 500000000 3.30 ns/op
|
||
|
|
BenchmarkRNGUint32nWithLock-4 20000000 88.7 ns/op
|
||
|
|
BenchmarkMathRandInt31n-4 10000000 145 ns/op
|
||
|
|
BenchmarkMathRandRNGInt31n-4 200000000 8.35 ns/op
|
||
|
|
BenchmarkMathRandRNGInt31nWithLock-4 20000000 102 ns/op
|
||
|
|
PASS
|
||
|
|
ok github.com/valyala/fastrand 11.534s
|
||
|
|
```
|
||
|
|
|
||
|
|
As you can see, [fastrand.Uint32n](https://godoc.org/github.com/valyala/fastrand#Uint32n)
|
||
|
|
scales on multiple CPUs, while [rand.Int31n](https://golang.org/pkg/math/rand/#Int31n)
|
||
|
|
doesn't scale. Their performance is comparable on `GOMAXPROCS=1`,
|
||
|
|
but `fastrand.Uint32n` runs 3x faster than `rand.Int31n` on `GOMAXPROCS=2`
|
||
|
|
and 10x faster than `rand.Int31n` on `GOMAXPROCS=4`.
|