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perf(fastrand): optimize Read #123

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merged 4 commits into from
Mar 23, 2022
Merged

perf(fastrand): optimize Read #123

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cf61946
fastrand: optimize Read
zhangyunhao116 Mar 21, 2022
acde172
fix feishu-notify
zhangyunhao116 Mar 21, 2022
dfd2703
fix feishu-notify
zhangyunhao116 Mar 21, 2022
c0b1d0b
fix feishu-notify
zhangyunhao116 Mar 21, 2022
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4 changes: 2 additions & 2 deletions .github/workflows/feishu-notify.yml
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Original file line number Diff line number Diff line change
Expand Up @@ -27,7 +27,7 @@ jobs:

run: |
sudo apt update
sudo apt install wget
sudo apt install wget -y
wget -q https://github.com/xiachufang/actions-feishu/releases/download/${{ env.ACTIONS_FEISHU_TAG }}/linux-amd64-actions-feishu.tar.gz
tar zxf linux-amd64-actions-feishu.tar.gz feishu
./feishu
Expand All @@ -52,7 +52,7 @@ jobs:

run: |
sudo apt update
sudo apt install wget
sudo apt install wget -y
wget -q https://github.com/xiachufang/actions-feishu/releases/download/${{ env.ACTIONS_FEISHU_TAG }}/linux-amd64-actions-feishu.tar.gz
tar zxf linux-amd64-actions-feishu.tar.gz feishu
./feishu
58 changes: 36 additions & 22 deletions lang/fastrand/fastrand.go
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Original file line number Diff line number Diff line change
Expand Up @@ -16,15 +16,14 @@
package fastrand

import (
"math/bits"
"unsafe"

"github.com/bytedance/gopkg/internal/runtimex"
)

// Uint32 returns a pseudo-random 32-bit value as a uint32.
func Uint32() uint32 {
return runtimex.Fastrand()
}
var Uint32 = runtimex.Fastrand

// Uint64 returns a pseudo-random 64-bit value as a uint64.
func Uint64() uint64 {
Expand Down Expand Up @@ -124,6 +123,33 @@ func Uint64n(n uint64) uint64 {
return Uint64() % n
}

// wyrand: https://github.com/wangyi-fudan/wyhash
type wyrand uint64

func _wymix(a, b uint64) uint64 {
hi, lo := bits.Mul64(a, b)
return hi ^ lo
}

func (r *wyrand) Uint64() uint64 {
*r += wyrand(0xa0761d6478bd642f)
return _wymix(uint64(*r), uint64(*r^wyrand(0xe7037ed1a0b428db)))
}

func (r *wyrand) Uint64n(n uint64) uint64 {
return r.Uint64() % n
}

func (r *wyrand) Uint32() uint32 {
return uint32(Uint64())
}

func (r *wyrand) Uint32n(n int) uint32 {
// This is similar to Uint32() % n, but faster.
// See https://lemire.me/blog/2016/06/27/a-fast-alternative-to-the-modulo-reduction/
return uint32(uint64(r.Uint32()) * uint64(n) >> 32)
}

// Read generates len(p) random bytes and writes them into p.
// It always returns len(p) and a nil error.
// It is safe for concurrent use.
Expand All @@ -133,33 +159,21 @@ func Read(p []byte) (int, error) {
return 0, nil
}

// Used for local XORSHIFT.
// Xorshift paper: https://www.jstatsoft.org/article/view/v008i14/xorshift.pdf
s0, s1 := Uint32(), Uint32()
r := wyrand(Uint32())

if l >= 4 {
if l >= 8 {
var i int
uint32p := *(*[]uint32)(unsafe.Pointer(&p))
for l >= 4 {
// Local XORSHIFT.
s1 ^= s1 << 17
s1 = s1 ^ s0 ^ s1>>7 ^ s0>>16
s0, s1 = s1, s0

uint32p[i] = s0 + s1
uint64p := *(*[]uint64)(unsafe.Pointer(&p))
for l >= 8 {
uint64p[i] = r.Uint64()
i++
l -= 4
l -= 8
}
}

if l > 0 {
// Local XORSHIFT.
s1 ^= s1 << 17
s1 = s1 ^ s0 ^ s1>>7 ^ s0>>16

r := s0 + s1
for l > 0 {
p[len(p)-l] = byte(r >> (l * 8))
p[len(p)-l] = byte(r.Uint64() >> (l * 8))
l--
}
}
Expand Down