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runtime: using wyhash for memhashFallback on 64bit platform

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wyhash is a general hash function that:

1. About 8-70% faster that internal maphash
2. Passed Smhasher, BigCrush and PractRand tests

name                  old time/op    new time/op    delta
Hash5                   28.9ns ± 0%    30.0ns ± 0%   +3.77%  (p=0.000 n=9+10)
Hash16                  32.4ns ± 0%    30.2ns ± 0%   -6.74%  (p=0.000 n=10+8)
Hash64                  52.4ns ± 0%    43.4ns ± 0%  -17.20%  (p=0.000 n=9+10)
Hash1024                 415ns ± 0%     258ns ± 2%  -37.89%  (p=0.000 n=10+10)
Hash65536               24.9µs ± 0%    14.6µs ± 0%  -41.22%  (p=0.000 n=9+9)
HashStringSpeed         50.2ns ± 4%    47.8ns ± 4%   -4.88%  (p=0.000 n=10+10)
HashBytesSpeed          90.1ns ± 7%    78.3ns ± 4%  -13.06%  (p=0.000 n=10+10)
HashInt32Speed          33.3ns ± 6%    33.6ns ± 4%     ~     (p=0.071 n=10+10)
HashInt64Speed          32.7ns ± 3%    34.0ns ± 3%   +4.05%  (p=0.000 n=9+10)
HashStringArraySpeed     131ns ± 2%     117ns ± 5%  -10.32%  (p=0.000 n=9+10)
FastrandHashiter        72.2ns ± 1%    75.7ns ±10%   +4.87%  (p=0.019 n=8+10)

name                  old speed      new speed      delta
Hash5                  173MB/s ± 0%   167MB/s ± 0%   -3.63%  (p=0.000 n=9+10)
Hash16                 494MB/s ± 0%   530MB/s ± 0%   +7.23%  (p=0.000 n=10+8)
Hash64                1.22GB/s ± 0%  1.48GB/s ± 0%  +20.77%  (p=0.000 n=9+10)
Hash1024              2.47GB/s ± 0%  3.97GB/s ± 2%  +61.01%  (p=0.000 n=8+10)
Hash65536             2.64GB/s ± 0%  4.48GB/s ± 0%  +70.13%  (p=0.000 n=9+9)

Change-Id: I76af4e2bc1995a18149d11983ea8a149c132865e
Reviewed-on: https://go-review.googlesource.com/c/go/+/279612
Trust: Meng Zhuo <mzh@golangcn.org>
Run-TryBot: Meng Zhuo <mzh@golangcn.org>
TryBot-Result: Go Bot <gobot@golang.org>
Reviewed-by: Keith Randall <khr@golang.org>
This commit is contained in:
Meng Zhuo 2021-04-08 16:08:55 +08:00
parent 424abc8d3b
commit 7beb988a3b
4 changed files with 84 additions and 78 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
src/cmd/compile/internal/ssagen/ssa.go
View File

@ -4484,6 +4484,7 @@ func InitTables() {
},
sys.AMD64, sys.ARM64, sys.PPC64, sys.S390X, sys.MIPS64)
alias("math/bits", "Mul", "math/bits", "Mul64", sys.ArchAMD64, sys.ArchARM64, sys.ArchPPC64, sys.ArchS390X, sys.ArchMIPS64, sys.ArchMIPS64LE)
alias("runtime/internal/math", "Mul64", "math/bits", "Mul64", sys.ArchAMD64, sys.ArchARM64, sys.ArchPPC64, sys.ArchS390X, sys.ArchMIPS64, sys.ArchMIPS64LE)
addF("math/bits", "Add64",
func(s *state, n *ir.CallExpr, args []*ssa.Value) *ssa.Value {
return s.newValue3(ssa.OpAdd64carry, types.NewTuple(types.Types[types.TUINT64], types.Types[types.TUINT64]), args[0], args[1], args[2])

4
src/cmd/compile/internal/test/inl_test.go
View File

@ -175,8 +175,8 @@ func TestIntendedInlining(t *testing.T) {
want["runtime/internal/sys"] = append(want["runtime/internal/sys"], "Bswap32")
}
if bits.UintSize == 64 {
// rotl_31 is only defined on 64-bit architectures
want["runtime"] = append(want["runtime"], "rotl_31")
// mix is only defined on 64-bit architectures
want["runtime"] = append(want["runtime"], "mix")
}
switch runtime.GOARCH {

136
src/runtime/hash64.go
View File

@ -3,107 +3,91 @@
// license that can be found in the LICENSE file.
// Hashing algorithm inspired by
// xxhash: https://code.google.com/p/xxhash/
// cityhash: https://code.google.com/p/cityhash/
// wyhash: https://github.com/wangyi-fudan/wyhash
//go:build amd64 || arm64 || mips64 || mips64le || ppc64 || ppc64le || riscv64 || s390x || wasm
// +build amd64 arm64 mips64 mips64le ppc64 ppc64le riscv64 s390x wasm
package runtime
import "unsafe"
import (
"runtime/internal/math"
"unsafe"
)
const (
// Constants for multiplication: four random odd 64-bit numbers.
m1 = 16877499708836156737
m2 = 2820277070424839065
m3 = 9497967016996688599
m4 = 15839092249703872147
m1 = 0xa0761d6478bd642f
m2 = 0xe7037ed1a0b428db
m3 = 0x8ebc6af09c88c6e3
m4 = 0x589965cc75374cc3
m5 = 0x1d8e4e27c47d124f
)
func memhashFallback(p unsafe.Pointer, seed, s uintptr) uintptr {
h := uint64(seed + s*hashkey[0])
tail:
var a, b uintptr
seed ^= hashkey[0] ^ m1
switch {
case s == 0:
return seed
case s < 4:
h ^= uint64(*(*byte)(p))
h ^= uint64(*(*byte)(add(p, s>>1))) << 8
h ^= uint64(*(*byte)(add(p, s-1))) << 16
h = rotl_31(h*m1) * m2
case s <= 8:
h ^= uint64(readUnaligned32(p))
h ^= uint64(readUnaligned32(add(p, s-4))) << 32
h = rotl_31(h*m1) * m2
a = uintptr(*(*byte)(p))
a |= uintptr(*(*byte)(add(p, s>>1))) << 8
a |= uintptr(*(*byte)(add(p, s-1))) << 16
case s == 4:
a = r4(p)
b = a
case s < 8:
a = r4(p)
b = r4(add(p, s-4))
case s == 8:
a = r8(p)
b = a
case s <= 16:
h ^= readUnaligned64(p)
h = rotl_31(h*m1) * m2
h ^= readUnaligned64(add(p, s-8))
h = rotl_31(h*m1) * m2
case s <= 32:
h ^= readUnaligned64(p)
h = rotl_31(h*m1) * m2
h ^= readUnaligned64(add(p, 8))
h = rotl_31(h*m1) * m2
h ^= readUnaligned64(add(p, s-16))
h = rotl_31(h*m1) * m2
h ^= readUnaligned64(add(p, s-8))
h = rotl_31(h*m1) * m2
a = r8(p)
b = r8(add(p, s-8))
default:
v1 := h
v2 := uint64(seed * hashkey[1])
v3 := uint64(seed * hashkey[2])
v4 := uint64(seed * hashkey[3])
for s >= 32 {
v1 ^= readUnaligned64(p)
v1 = rotl_31(v1*m1) * m2
p = add(p, 8)
v2 ^= readUnaligned64(p)
v2 = rotl_31(v2*m2) * m3
p = add(p, 8)
v3 ^= readUnaligned64(p)
v3 = rotl_31(v3*m3) * m4
p = add(p, 8)
v4 ^= readUnaligned64(p)
v4 = rotl_31(v4*m4) * m1
p = add(p, 8)
s -= 32
l := s
if l > 48 {
seed1 := seed
seed2 := seed
for ; l > 48; l -= 48 {
seed = mix(r8(p)^m2, r8(add(p, 8))^seed)
seed1 = mix(r8(add(p, 16))^m3, r8(add(p, 24))^seed1)
seed2 = mix(r8(add(p, 32))^m4, r8(add(p, 40))^seed2)
p = add(p, 48)
}
h = v1 ^ v2 ^ v3 ^ v4
goto tail
seed ^= seed1 ^ seed2
}
for ; l > 16; l -= 16 {
seed = mix(r8(p)^m2, r8(add(p, 8))^seed)
p = add(p, 16)
}
a = r8(add(p, l-16))
b = r8(add(p, l-8))
}
h ^= h >> 29
h *= m3
h ^= h >> 32
return uintptr(h)
return mix(m5^s, mix(a^m2, b^seed))
}
func memhash32Fallback(p unsafe.Pointer, seed uintptr) uintptr {
h := uint64(seed + 4*hashkey[0])
v := uint64(readUnaligned32(p))
h ^= v
h ^= v << 32
h = rotl_31(h*m1) * m2
h ^= h >> 29
h *= m3
h ^= h >> 32
return uintptr(h)
a := r4(p)
return mix(m5^4, mix(a^m2, a^seed^hashkey[0]^m1))
}
func memhash64Fallback(p unsafe.Pointer, seed uintptr) uintptr {
h := uint64(seed + 8*hashkey[0])
h ^= uint64(readUnaligned32(p)) | uint64(readUnaligned32(add(p, 4)))<<32
h = rotl_31(h*m1) * m2
h ^= h >> 29
h *= m3
h ^= h >> 32
return uintptr(h)
a := r8(p)
return mix(m5^8, mix(a^m2, a^seed^hashkey[0]^m1))
}
// Note: in order to get the compiler to issue rotl instructions, we
// need to constant fold the shift amount by hand.
// TODO: convince the compiler to issue rotl instructions after inlining.
func rotl_31(x uint64) uint64 {
return (x << 31) | (x >> (64 - 31))
func mix(a, b uintptr) uintptr {
hi, lo := math.Mul64(uint64(a), uint64(b))
return uintptr(hi ^ lo)
}
func r4(p unsafe.Pointer) uintptr {
return uintptr(readUnaligned32(p))
}
func r8(p unsafe.Pointer) uintptr {
return uintptr(readUnaligned64(p))
}

21
src/runtime/internal/math/math.go
View File

@ -17,3 +17,24 @@ func MulUintptr(a, b uintptr) (uintptr, bool) {
overflow := b > MaxUintptr/a
return a * b, overflow
}
// Mul64 returns the 128-bit product of x and y: (hi, lo) = x * y
// with the product bits' upper half returned in hi and the lower
// half returned in lo.
// This is a copy from math/bits.Mul64
// On supported platforms this is an intrinsic lowered by the compiler.
func Mul64(x, y uint64) (hi, lo uint64) {
const mask32 = 1<<32 - 1
x0 := x & mask32
x1 := x >> 32
y0 := y & mask32
y1 := y >> 32
w0 := x0 * y0
t := x1*y0 + w0>>32
w1 := t & mask32
w2 := t >> 32
w1 += x0 * y1
hi = x1*y1 + w2 + w1>>32
lo = x * y
return
}