labels: Reduce allocated memory and latency of Hash method; Added tests. (#8025)

* labels: Reduce allocated memory by Hash method in edge cases; Added tests.

Old:
/tmp/___BenchmarkLabels_Hash_in_github_com_prometheus_prometheus_pkg_labels -test.v -test.bench ^\QBenchmarkLabels_Hash\E$ -test.run ^$
goos: linux
goarch: amd64
pkg: github.com/prometheus/prometheus/pkg/labels
BenchmarkLabels_Hash
BenchmarkLabels_Hash/typical_labels_under_1KB
BenchmarkLabels_Hash/typical_labels_under_1KB-12         	 5366161	       259 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabels_Hash/bigger_labels_over_1KB
BenchmarkLabels_Hash/bigger_labels_over_1KB-12           	 1700371	       767 ns/op	    2048 B/op	       1 allocs/op
BenchmarkLabels_Hash/extremely_large_label_value_10MB
BenchmarkLabels_Hash/extremely_large_label_value_10MB-12 	     356	   3743115 ns/op	10523442 B/op	       1 allocs/op
PASS

New:
/tmp/___BenchmarkLabels_Hash_in_github_com_prometheus_prometheus_pkg_labels -test.v -test.bench ^\QBenchmarkLabels_Hash\E$ -test.run ^$
goos: linux
goarch: amd64
pkg: github.com/prometheus/prometheus/pkg/labels
BenchmarkLabels_Hash
BenchmarkLabels_Hash/typical_labels_under_1KB
BenchmarkLabels_Hash/typical_labels_under_1KB-12         	 4758883	       259 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabels_Hash/bigger_labels_over_1KB
BenchmarkLabels_Hash/bigger_labels_over_1KB-12           	 3324492	       357 ns/op	      80 B/op	       1 allocs/op
BenchmarkLabels_Hash/extremely_large_label_value_10MB
BenchmarkLabels_Hash/extremely_large_label_value_10MB-12 	    1087	   1083949 ns/op	    9734 B/op	       1 allocs/op
PASS

Process finished with exit code 0

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Addressed Kemal's comment.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Moved to v2 xxhash for improvements.

New:

/tmp/___BenchmarkLabels_Hash_in_github_com_prometheus_prometheus_pkg_labels -test.v -test.bench ^\QBenchmarkLabels_Hash\E$ -test.run ^$ -test.benchtime 10s
goos: linux
goarch: amd64
pkg: github.com/prometheus/prometheus/pkg/labels
BenchmarkLabels_Hash
BenchmarkLabels_Hash/typical_labels_under_1KB
BenchmarkLabels_Hash/typical_labels_under_1KB-12         	53447894	       221 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabels_Hash/bigger_labels_over_1KB
BenchmarkLabels_Hash/bigger_labels_over_1KB-12           	42341754	       326 ns/op	       0 B/op	       0 allocs/op
BenchmarkLabels_Hash/extremely_large_label_value_10MB
BenchmarkLabels_Hash/extremely_large_label_value_10MB-12 	   10000	   1248546 ns/op	       0 B/op	       0 allocs/op
PASS

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Removed old xxhash package.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>

* Pined minor version.

Signed-off-by: Bartlomiej Plotka <bwplotka@gmail.com>
This commit is contained in:
Bartlomiej Plotka 2020-10-15 12:31:28 +02:00 committed by GitHub
parent d49f267f76
commit 9981b3f3ee
No known key found for this signature in database
GPG key ID: 4AEE18F83AFDEB23
17 changed files with 95 additions and 654 deletions

2
go.mod
View file

@ -14,7 +14,7 @@ require (
github.com/alecthomas/units v0.0.0-20190924025748-f65c72e2690d
github.com/armon/go-metrics v0.3.3 // indirect
github.com/aws/aws-sdk-go v1.35.5
github.com/cespare/xxhash v1.1.0
github.com/cespare/xxhash/v2 v2.1.1
github.com/containerd/containerd v1.3.4 // indirect
github.com/davecgh/go-spew v1.1.1
github.com/dgryski/go-sip13 v0.0.0-20200911182023-62edffca9245

View file

@ -19,7 +19,7 @@ import (
"sort"
"strconv"
"github.com/cespare/xxhash"
"github.com/cespare/xxhash/v2"
)
// Well-known label names used by Prometheus components.
@ -29,10 +29,11 @@ const (
BucketLabel = "le"
InstanceName = "instance"
sep = '\xff'
labelSep = '\xfe'
)
var seps = []byte{'\xff'}
// Label is a key/value pair of strings.
type Label struct {
Name, Value string
@ -70,10 +71,10 @@ func (ls Labels) Bytes(buf []byte) []byte {
b.WriteByte(labelSep)
for i, l := range ls {
if i > 0 {
b.WriteByte(sep)
b.WriteByte(seps[0])
}
b.WriteString(l.Name)
b.WriteByte(sep)
b.WriteByte(seps[0])
b.WriteString(l.Value)
}
return b.Bytes()
@ -134,13 +135,26 @@ func (ls Labels) MatchLabels(on bool, names ...string) Labels {
// Hash returns a hash value for the label set.
func (ls Labels) Hash() uint64 {
// Use xxhash.Sum64(b) for fast path as it's faster.
b := make([]byte, 0, 1024)
for i, v := range ls {
if len(b)+len(v.Name)+len(v.Value)+2 >= cap(b) {
// If labels entry is 1KB+ do not allocate whole entry.
h := xxhash.New()
_, _ = h.Write(b)
for _, v := range ls[i:] {
_, _ = h.WriteString(v.Name)
_, _ = h.Write(seps)
_, _ = h.WriteString(v.Value)
_, _ = h.Write(seps)
}
return h.Sum64()
}
for _, v := range ls {
b = append(b, v.Name...)
b = append(b, sep)
b = append(b, seps[0])
b = append(b, v.Value...)
b = append(b, sep)
b = append(b, seps[0])
}
return xxhash.Sum64(b)
}
@ -157,9 +171,9 @@ func (ls Labels) HashForLabels(b []byte, names ...string) (uint64, []byte) {
i++
} else {
b = append(b, ls[i].Name...)
b = append(b, sep)
b = append(b, seps[0])
b = append(b, ls[i].Value...)
b = append(b, sep)
b = append(b, seps[0])
i++
j++
}
@ -181,9 +195,9 @@ func (ls Labels) HashWithoutLabels(b []byte, names ...string) (uint64, []byte) {
continue
}
b = append(b, ls[i].Name...)
b = append(b, sep)
b = append(b, seps[0])
b = append(b, ls[i].Value...)
b = append(b, sep)
b = append(b, seps[0])
}
return xxhash.Sum64(b), b
}

View file

@ -14,6 +14,8 @@
package labels
import (
"fmt"
"strings"
"testing"
"github.com/prometheus/prometheus/util/testutil"
@ -631,3 +633,68 @@ func TestBuilder_Labels(t *testing.T) {
}).Labels(),
)
}
func TestLabels_Hash(t *testing.T) {
lbls := Labels{
{Name: "foo", Value: "bar"},
{Name: "baz", Value: "qux"},
}
testutil.Equals(t, lbls.Hash(), lbls.Hash())
testutil.Assert(t, lbls.Hash() != Labels{lbls[1], lbls[0]}.Hash(), "unordered labels match.")
testutil.Assert(t, lbls.Hash() != Labels{lbls[0]}.Hash(), "different labels match.")
}
var benchmarkLabelsResult uint64
func BenchmarkLabels_Hash(b *testing.B) {
for _, tcase := range []struct {
name string
lbls Labels
}{
{
name: "typical labels under 1KB",
lbls: func() Labels {
lbls := make(Labels, 10)
for i := 0; i < len(lbls); i++ {
// Label ~20B name, 50B value.
lbls[i] = Label{Name: fmt.Sprintf("abcdefghijabcdefghijabcdefghij%d", i), Value: fmt.Sprintf("abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij%d", i)}
}
return lbls
}(),
},
{
name: "bigger labels over 1KB",
lbls: func() Labels {
lbls := make(Labels, 10)
for i := 0; i < len(lbls); i++ {
//Label ~50B name, 50B value.
lbls[i] = Label{Name: fmt.Sprintf("abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij%d", i), Value: fmt.Sprintf("abcdefghijabcdefghijabcdefghijabcdefghijabcdefghij%d", i)}
}
return lbls
}(),
},
{
name: "extremely large label value 10MB",
lbls: func() Labels {
lbl := &strings.Builder{}
lbl.Grow(1024 * 1024 * 10) // 10MB.
word := "abcdefghij"
for i := 0; i < lbl.Cap()/len(word); i++ {
_, _ = lbl.WriteString(word)
}
return Labels{{Name: "__name__", Value: lbl.String()}}
}(),
},
} {
b.Run(tcase.name, func(b *testing.B) {
var h uint64
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
h = tcase.lbls.Hash()
}
benchmarkLabelsResult = h
})
}
}

View file

@ -19,7 +19,7 @@ import (
"hash/crc32"
"testing"
"github.com/cespare/xxhash"
"github.com/cespare/xxhash/v2"
sip13 "github.com/dgryski/go-sip13"
)

View file

@ -1,22 +0,0 @@
Copyright (c) 2016 Caleb Spare
MIT License
Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
"Software"), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:
The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

View file

@ -1,50 +0,0 @@
# xxhash
[![GoDoc](https://godoc.org/github.com/cespare/xxhash?status.svg)](https://godoc.org/github.com/cespare/xxhash)
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.
The API is very small, taking its cue from the other hashing packages in the
standard library:
$ go doc github.com/cespare/xxhash !
package xxhash // import "github.com/cespare/xxhash"
Package xxhash implements the 64-bit variant of xxHash (XXH64) as described
at http://cyan4973.github.io/xxHash/.
func New() hash.Hash64
func Sum64(b []byte) uint64
func Sum64String(s string) uint64
This implementation provides a fast pure-Go implementation and an even faster
assembly implementation for amd64.
## Benchmarks
Here are some quick benchmarks comparing the pure-Go and assembly
implementations of Sum64 against another popular Go XXH64 implementation,
[github.com/OneOfOne/xxhash](https://github.com/OneOfOne/xxhash):
| input size | OneOfOne | cespare (purego) | cespare |
| --- | --- | --- | --- |
| 5 B | 416 MB/s | 720 MB/s | 872 MB/s |
| 100 B | 3980 MB/s | 5013 MB/s | 5252 MB/s |
| 4 KB | 12727 MB/s | 12999 MB/s | 13026 MB/s |
| 10 MB | 9879 MB/s | 10775 MB/s | 10913 MB/s |
These numbers were generated with:
```
$ go test -benchtime 10s -bench '/OneOfOne,'
$ go test -tags purego -benchtime 10s -bench '/xxhash,'
$ go test -benchtime 10s -bench '/xxhash,'
```
## Projects using this package
- [InfluxDB](https://github.com/influxdata/influxdb)
- [Prometheus](https://github.com/prometheus/prometheus)

View file

@ -1,6 +0,0 @@
module github.com/cespare/xxhash
require (
github.com/OneOfOne/xxhash v1.2.2
github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72
)

View file

@ -1,4 +0,0 @@
github.com/OneOfOne/xxhash v1.2.2 h1:KMrpdQIwFcEqXDklaen+P1axHaj9BSKzvpUUfnHldSE=
github.com/OneOfOne/xxhash v1.2.2/go.mod h1:HSdplMjZKSmBqAxg5vPj2TmRDmfkzw+cTzAElWljhcU=
github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72 h1:qLC7fQah7D6K1B0ujays3HV9gkFtllcxhzImRR7ArPQ=
github.com/spaolacci/murmur3 v0.0.0-20180118202830-f09979ecbc72/go.mod h1:JwIasOWyU6f++ZhiEuf87xNszmSA2myDM2Kzu9HwQUA=

View file

@ -1,14 +0,0 @@
// +build !go1.9
package xxhash
// TODO(caleb): After Go 1.10 comes out, remove this fallback code.
func rol1(x uint64) uint64 { return (x << 1) | (x >> (64 - 1)) }
func rol7(x uint64) uint64 { return (x << 7) | (x >> (64 - 7)) }
func rol11(x uint64) uint64 { return (x << 11) | (x >> (64 - 11)) }
func rol12(x uint64) uint64 { return (x << 12) | (x >> (64 - 12)) }
func rol18(x uint64) uint64 { return (x << 18) | (x >> (64 - 18)) }
func rol23(x uint64) uint64 { return (x << 23) | (x >> (64 - 23)) }
func rol27(x uint64) uint64 { return (x << 27) | (x >> (64 - 27)) }
func rol31(x uint64) uint64 { return (x << 31) | (x >> (64 - 31)) }

View file

@ -1,14 +0,0 @@
// +build go1.9
package xxhash
import "math/bits"
func rol1(x uint64) uint64 { return bits.RotateLeft64(x, 1) }
func rol7(x uint64) uint64 { return bits.RotateLeft64(x, 7) }
func rol11(x uint64) uint64 { return bits.RotateLeft64(x, 11) }
func rol12(x uint64) uint64 { return bits.RotateLeft64(x, 12) }
func rol18(x uint64) uint64 { return bits.RotateLeft64(x, 18) }
func rol23(x uint64) uint64 { return bits.RotateLeft64(x, 23) }
func rol27(x uint64) uint64 { return bits.RotateLeft64(x, 27) }
func rol31(x uint64) uint64 { return bits.RotateLeft64(x, 31) }

View file

@ -1,168 +0,0 @@
// Package xxhash implements the 64-bit variant of xxHash (XXH64) as described
// at http://cyan4973.github.io/xxHash/.
package xxhash
import (
"encoding/binary"
"hash"
)
const (
prime1 uint64 = 11400714785074694791
prime2 uint64 = 14029467366897019727
prime3 uint64 = 1609587929392839161
prime4 uint64 = 9650029242287828579
prime5 uint64 = 2870177450012600261
)
// NOTE(caleb): I'm using both consts and vars of the primes. Using consts where
// possible in the Go code is worth a small (but measurable) performance boost
// by avoiding some MOVQs. Vars are needed for the asm and also are useful for
// convenience in the Go code in a few places where we need to intentionally
// avoid constant arithmetic (e.g., v1 := prime1 + prime2 fails because the
// result overflows a uint64).
var (
prime1v = prime1
prime2v = prime2
prime3v = prime3
prime4v = prime4
prime5v = prime5
)
type xxh struct {
v1 uint64
v2 uint64
v3 uint64
v4 uint64
total int
mem [32]byte
n int // how much of mem is used
}
// New creates a new hash.Hash64 that implements the 64-bit xxHash algorithm.
func New() hash.Hash64 {
var x xxh
x.Reset()
return &x
}
func (x *xxh) Reset() {
x.n = 0
x.total = 0
x.v1 = prime1v + prime2
x.v2 = prime2
x.v3 = 0
x.v4 = -prime1v
}
func (x *xxh) Size() int { return 8 }
func (x *xxh) BlockSize() int { return 32 }
// Write adds more data to x. It always returns len(b), nil.
func (x *xxh) Write(b []byte) (n int, err error) {
n = len(b)
x.total += len(b)
if x.n+len(b) < 32 {
// This new data doesn't even fill the current block.
copy(x.mem[x.n:], b)
x.n += len(b)
return
}
if x.n > 0 {
// Finish off the partial block.
copy(x.mem[x.n:], b)
x.v1 = round(x.v1, u64(x.mem[0:8]))
x.v2 = round(x.v2, u64(x.mem[8:16]))
x.v3 = round(x.v3, u64(x.mem[16:24]))
x.v4 = round(x.v4, u64(x.mem[24:32]))
b = b[32-x.n:]
x.n = 0
}
if len(b) >= 32 {
// One or more full blocks left.
b = writeBlocks(x, b)
}
// Store any remaining partial block.
copy(x.mem[:], b)
x.n = len(b)
return
}
func (x *xxh) Sum(b []byte) []byte {
s := x.Sum64()
return append(
b,
byte(s>>56),
byte(s>>48),
byte(s>>40),
byte(s>>32),
byte(s>>24),
byte(s>>16),
byte(s>>8),
byte(s),
)
}
func (x *xxh) Sum64() uint64 {
var h uint64
if x.total >= 32 {
v1, v2, v3, v4 := x.v1, x.v2, x.v3, x.v4
h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
h = mergeRound(h, v1)
h = mergeRound(h, v2)
h = mergeRound(h, v3)
h = mergeRound(h, v4)
} else {
h = x.v3 + prime5
}
h += uint64(x.total)
i, end := 0, x.n
for ; i+8 <= end; i += 8 {
k1 := round(0, u64(x.mem[i:i+8]))
h ^= k1
h = rol27(h)*prime1 + prime4
}
if i+4 <= end {
h ^= uint64(u32(x.mem[i:i+4])) * prime1
h = rol23(h)*prime2 + prime3
i += 4
}
for i < end {
h ^= uint64(x.mem[i]) * prime5
h = rol11(h) * prime1
i++
}
h ^= h >> 33
h *= prime2
h ^= h >> 29
h *= prime3
h ^= h >> 32
return h
}
func u64(b []byte) uint64 { return binary.LittleEndian.Uint64(b) }
func u32(b []byte) uint32 { return binary.LittleEndian.Uint32(b) }
func round(acc, input uint64) uint64 {
acc += input * prime2
acc = rol31(acc)
acc *= prime1
return acc
}
func mergeRound(acc, val uint64) uint64 {
val = round(0, val)
acc ^= val
acc = acc*prime1 + prime4
return acc
}

View file

@ -1,12 +0,0 @@
// +build !appengine
// +build gc
// +build !purego
package xxhash
// Sum64 computes the 64-bit xxHash digest of b.
//
//go:noescape
func Sum64(b []byte) uint64
func writeBlocks(x *xxh, b []byte) []byte

View file

@ -1,233 +0,0 @@
// +build !appengine
// +build gc
// +build !purego
#include "textflag.h"
// Register allocation:
// AX h
// CX pointer to advance through b
// DX n
// BX loop end
// R8 v1, k1
// R9 v2
// R10 v3
// R11 v4
// R12 tmp
// R13 prime1v
// R14 prime2v
// R15 prime4v
// round reads from and advances the buffer pointer in CX.
// It assumes that R13 has prime1v and R14 has prime2v.
#define round(r) \
MOVQ (CX), R12 \
ADDQ $8, CX \
IMULQ R14, R12 \
ADDQ R12, r \
ROLQ $31, r \
IMULQ R13, r
// mergeRound applies a merge round on the two registers acc and val.
// It assumes that R13 has prime1v, R14 has prime2v, and R15 has prime4v.
#define mergeRound(acc, val) \
IMULQ R14, val \
ROLQ $31, val \
IMULQ R13, val \
XORQ val, acc \
IMULQ R13, acc \
ADDQ R15, acc
// func Sum64(b []byte) uint64
TEXT ·Sum64(SB), NOSPLIT, $0-32
// Load fixed primes.
MOVQ ·prime1v(SB), R13
MOVQ ·prime2v(SB), R14
MOVQ ·prime4v(SB), R15
// Load slice.
MOVQ b_base+0(FP), CX
MOVQ b_len+8(FP), DX
LEAQ (CX)(DX*1), BX
// The first loop limit will be len(b)-32.
SUBQ $32, BX
// Check whether we have at least one block.
CMPQ DX, $32
JLT noBlocks
// Set up initial state (v1, v2, v3, v4).
MOVQ R13, R8
ADDQ R14, R8
MOVQ R14, R9
XORQ R10, R10
XORQ R11, R11
SUBQ R13, R11
// Loop until CX > BX.
blockLoop:
round(R8)
round(R9)
round(R10)
round(R11)
CMPQ CX, BX
JLE blockLoop
MOVQ R8, AX
ROLQ $1, AX
MOVQ R9, R12
ROLQ $7, R12
ADDQ R12, AX
MOVQ R10, R12
ROLQ $12, R12
ADDQ R12, AX
MOVQ R11, R12
ROLQ $18, R12
ADDQ R12, AX
mergeRound(AX, R8)
mergeRound(AX, R9)
mergeRound(AX, R10)
mergeRound(AX, R11)
JMP afterBlocks
noBlocks:
MOVQ ·prime5v(SB), AX
afterBlocks:
ADDQ DX, AX
// Right now BX has len(b)-32, and we want to loop until CX > len(b)-8.
ADDQ $24, BX
CMPQ CX, BX
JG fourByte
wordLoop:
// Calculate k1.
MOVQ (CX), R8
ADDQ $8, CX
IMULQ R14, R8
ROLQ $31, R8
IMULQ R13, R8
XORQ R8, AX
ROLQ $27, AX
IMULQ R13, AX
ADDQ R15, AX
CMPQ CX, BX
JLE wordLoop
fourByte:
ADDQ $4, BX
CMPQ CX, BX
JG singles
MOVL (CX), R8
ADDQ $4, CX
IMULQ R13, R8
XORQ R8, AX
ROLQ $23, AX
IMULQ R14, AX
ADDQ ·prime3v(SB), AX
singles:
ADDQ $4, BX
CMPQ CX, BX
JGE finalize
singlesLoop:
MOVBQZX (CX), R12
ADDQ $1, CX
IMULQ ·prime5v(SB), R12
XORQ R12, AX
ROLQ $11, AX
IMULQ R13, AX
CMPQ CX, BX
JL singlesLoop
finalize:
MOVQ AX, R12
SHRQ $33, R12
XORQ R12, AX
IMULQ R14, AX
MOVQ AX, R12
SHRQ $29, R12
XORQ R12, AX
IMULQ ·prime3v(SB), AX
MOVQ AX, R12
SHRQ $32, R12
XORQ R12, AX
MOVQ AX, ret+24(FP)
RET
// writeBlocks uses the same registers as above except that it uses AX to store
// the x pointer.
// func writeBlocks(x *xxh, b []byte) []byte
TEXT ·writeBlocks(SB), NOSPLIT, $0-56
// Load fixed primes needed for round.
MOVQ ·prime1v(SB), R13
MOVQ ·prime2v(SB), R14
// Load slice.
MOVQ b_base+8(FP), CX
MOVQ CX, ret_base+32(FP) // initialize return base pointer; see NOTE below
MOVQ b_len+16(FP), DX
LEAQ (CX)(DX*1), BX
SUBQ $32, BX
// Load vN from x.
MOVQ x+0(FP), AX
MOVQ 0(AX), R8 // v1
MOVQ 8(AX), R9 // v2
MOVQ 16(AX), R10 // v3
MOVQ 24(AX), R11 // v4
// We don't need to check the loop condition here; this function is
// always called with at least one block of data to process.
blockLoop:
round(R8)
round(R9)
round(R10)
round(R11)
CMPQ CX, BX
JLE blockLoop
// Copy vN back to x.
MOVQ R8, 0(AX)
MOVQ R9, 8(AX)
MOVQ R10, 16(AX)
MOVQ R11, 24(AX)
// Construct return slice.
// NOTE: It's important that we don't construct a slice that has a base
// pointer off the end of the original slice, as in Go 1.7+ this will
// cause runtime crashes. (See discussion in, for example,
// https://github.com/golang/go/issues/16772.)
// Therefore, we calculate the length/cap first, and if they're zero, we
// keep the old base. This is what the compiler does as well if you
// write code like
// b = b[len(b):]
// New length is 32 - (CX - BX) -> BX+32 - CX.
ADDQ $32, BX
SUBQ CX, BX
JZ afterSetBase
MOVQ CX, ret_base+32(FP)
afterSetBase:
MOVQ BX, ret_len+40(FP)
MOVQ BX, ret_cap+48(FP) // set cap == len
RET

View file

@ -1,75 +0,0 @@
// +build !amd64 appengine !gc purego
package xxhash
// Sum64 computes the 64-bit xxHash digest of b.
func Sum64(b []byte) uint64 {
// A simpler version would be
// x := New()
// x.Write(b)
// return x.Sum64()
// but this is faster, particularly for small inputs.
n := len(b)
var h uint64
if n >= 32 {
v1 := prime1v + prime2
v2 := prime2
v3 := uint64(0)
v4 := -prime1v
for len(b) >= 32 {
v1 = round(v1, u64(b[0:8:len(b)]))
v2 = round(v2, u64(b[8:16:len(b)]))
v3 = round(v3, u64(b[16:24:len(b)]))
v4 = round(v4, u64(b[24:32:len(b)]))
b = b[32:len(b):len(b)]
}
h = rol1(v1) + rol7(v2) + rol12(v3) + rol18(v4)
h = mergeRound(h, v1)
h = mergeRound(h, v2)
h = mergeRound(h, v3)
h = mergeRound(h, v4)
} else {
h = prime5
}
h += uint64(n)
i, end := 0, len(b)
for ; i+8 <= end; i += 8 {
k1 := round(0, u64(b[i:i+8:len(b)]))
h ^= k1
h = rol27(h)*prime1 + prime4
}
if i+4 <= end {
h ^= uint64(u32(b[i:i+4:len(b)])) * prime1
h = rol23(h)*prime2 + prime3
i += 4
}
for ; i < end; i++ {
h ^= uint64(b[i]) * prime5
h = rol11(h) * prime1
}
h ^= h >> 33
h *= prime2
h ^= h >> 29
h *= prime3
h ^= h >> 32
return h
}
func writeBlocks(x *xxh, b []byte) []byte {
v1, v2, v3, v4 := x.v1, x.v2, x.v3, x.v4
for len(b) >= 32 {
v1 = round(v1, u64(b[0:8:len(b)]))
v2 = round(v2, u64(b[8:16:len(b)]))
v3 = round(v3, u64(b[16:24:len(b)]))
v4 = round(v4, u64(b[24:32:len(b)]))
b = b[32:len(b):len(b)]
}
x.v1, x.v2, x.v3, x.v4 = v1, v2, v3, v4
return b
}

View file

@ -1,10 +0,0 @@
// +build appengine
// This file contains the safe implementations of otherwise unsafe-using code.
package xxhash
// Sum64String computes the 64-bit xxHash digest of s.
func Sum64String(s string) uint64 {
return Sum64([]byte(s))
}

View file

@ -1,30 +0,0 @@
// +build !appengine
// This file encapsulates usage of unsafe.
// xxhash_safe.go contains the safe implementations.
package xxhash
import (
"reflect"
"unsafe"
)
// Sum64String computes the 64-bit xxHash digest of s.
// It may be faster than Sum64([]byte(s)) by avoiding a copy.
//
// TODO(caleb): Consider removing this if an optimization is ever added to make
// it unnecessary: https://golang.org/issue/2205.
//
// TODO(caleb): We still have a function call; we could instead write Go/asm
// copies of Sum64 for strings to squeeze out a bit more speed.
func Sum64String(s string) uint64 {
// See https://groups.google.com/d/msg/golang-nuts/dcjzJy-bSpw/tcZYBzQqAQAJ
// for some discussion about this unsafe conversion.
var b []byte
bh := (*reflect.SliceHeader)(unsafe.Pointer(&b))
bh.Data = (*reflect.StringHeader)(unsafe.Pointer(&s)).Data
bh.Len = len(s)
bh.Cap = len(s)
return Sum64(b)
}

4
vendor/modules.txt vendored
View file

@ -90,10 +90,8 @@ github.com/aws/aws-sdk-go/service/sts
github.com/aws/aws-sdk-go/service/sts/stsiface
# github.com/beorn7/perks v1.0.1
github.com/beorn7/perks/quantile
# github.com/cespare/xxhash v1.1.0
## explicit
github.com/cespare/xxhash
# github.com/cespare/xxhash/v2 v2.1.1
## explicit
github.com/cespare/xxhash/v2
# github.com/containerd/containerd v1.3.4
## explicit