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mirror of https://github.com/golang/go synced 2024-11-21 20:14:52 -07:00

unicode: performance improvements (API change)

*** There is an API change here: the introduction of the
LatinOffset int in the RangeTable struct. ***

* Avoid checking Latin range multiple times for non-Latin runes.
* Use linear search when it is faster than binary search.

go test -calibrate runs the calibration for where the linear/binary
crossover should be.

benchmark                       old MB/s     new MB/s  speedup
BenchmarkFields            36.27        41.43    1.14x
BenchmarkFieldsFunc        36.23        41.38    1.14x

The speedup here is evenly split between the linear scans
and the LatinOffset change. Both are about 1.07x.

R=r
CC=bradfitz, gobot, golang-dev
https://golang.org/cl/6526048
This commit is contained in:
Russ Cox 2012-09-21 00:35:25 -04:00
parent 31758b2c1a
commit 4591cd631d
6 changed files with 232 additions and 30 deletions

View File

@ -9,5 +9,5 @@ func IsDigit(r rune) bool {
if r <= MaxLatin1 {
return '0' <= r && r <= '9'
}
return Is(Digit, r)
return isExcludingLatin(Digit, r)
}

View File

@ -78,13 +78,13 @@ func IsLetter(r rune) bool {
if uint32(r) <= MaxLatin1 {
return properties[uint8(r)]&(pLu|pLl) != 0
}
return Is(Letter, r)
return isExcludingLatin(Letter, r)
}
// IsMark reports whether the rune is a mark character (category M).
func IsMark(r rune) bool {
// There are no mark characters in Latin-1.
return Is(Mark, r)
return isExcludingLatin(Mark, r)
}
// IsNumber reports whether the rune is a number (category N).
@ -92,7 +92,7 @@ func IsNumber(r rune) bool {
if uint32(r) <= MaxLatin1 {
return properties[uint8(r)]&pN != 0
}
return Is(Number, r)
return isExcludingLatin(Number, r)
}
// IsPunct reports whether the rune is a Unicode punctuation character
@ -119,7 +119,7 @@ func IsSpace(r rune) bool {
}
return false
}
return Is(White_Space, r)
return isExcludingLatin(White_Space, r)
}
// IsSymbol reports whether the rune is a symbolic character.
@ -127,5 +127,5 @@ func IsSymbol(r rune) bool {
if uint32(r) <= MaxLatin1 {
return properties[uint8(r)]&pS != 0
}
return Is(Symbol, r)
return isExcludingLatin(Symbol, r)
}

View File

@ -19,8 +19,9 @@ const (
// The two slices must be in sorted order and non-overlapping.
// Also, R32 should contain only values >= 0x10000 (1<<16).
type RangeTable struct {
R16 []Range16
R32 []Range32
R16 []Range16
R32 []Range32
LatinOffset int // number of entries in R16 with Hi <= MaxLatin1
}
// Range16 represents of a range of 16-bit Unicode code points. The range runs from Lo to Hi
@ -80,14 +81,31 @@ const (
UpperLower = MaxRune + 1 // (Cannot be a valid delta.)
)
// is16 uses binary search to test whether rune is in the specified slice of 16-bit ranges.
// linearMax is the maximum size table for linear search for non-Latin1 rune.
// Derived by running 'go test -calibrate'.
const linearMax = 18
// is16 reports whether r is in the sorted slice of 16-bit ranges.
func is16(ranges []Range16, r uint16) bool {
if len(ranges) <= linearMax || r <= MaxLatin1 {
for i := range ranges {
range_ := &ranges[i]
if r < range_.Lo {
return false
}
if r <= range_.Hi {
return (r-range_.Lo)%range_.Stride == 0
}
}
return false
}
// binary search over ranges
lo := 0
hi := len(ranges)
for lo < hi {
m := lo + (hi-lo)/2
range_ := ranges[m]
range_ := &ranges[m]
if range_.Lo <= r && r <= range_.Hi {
return (r-range_.Lo)%range_.Stride == 0
}
@ -100,8 +118,21 @@ func is16(ranges []Range16, r uint16) bool {
return false
}
// is32 uses binary search to test whether rune is in the specified slice of 32-bit ranges.
// is32 reports whether r is in the sorted slice of 32-bit ranges.
func is32(ranges []Range32, r uint32) bool {
if len(ranges) <= linearMax {
for i := range ranges {
range_ := &ranges[i]
if r < range_.Lo {
return false
}
if r <= range_.Hi {
return (r-range_.Lo)%range_.Stride == 0
}
}
return false
}
// binary search over ranges
lo := 0
hi := len(ranges)
@ -122,21 +153,6 @@ func is32(ranges []Range32, r uint32) bool {
// Is tests whether rune is in the specified table of ranges.
func Is(rangeTab *RangeTable, r rune) bool {
// common case: rune is ASCII or Latin-1.
if uint32(r) <= MaxLatin1 {
// Only need to check R16, since R32 is always >= 1<<16.
r16 := uint16(r)
for _, r := range rangeTab.R16 {
if r16 > r.Hi {
continue
}
if r16 < r.Lo {
return false
}
return (r16-r.Lo)%r.Stride == 0
}
return false
}
r16 := rangeTab.R16
if len(r16) > 0 && r <= rune(r16[len(r16)-1].Hi) {
return is16(r16, uint16(r))
@ -148,13 +164,25 @@ func Is(rangeTab *RangeTable, r rune) bool {
return false
}
func isExcludingLatin(rangeTab *RangeTable, r rune) bool {
r16 := rangeTab.R16
if off := rangeTab.LatinOffset; len(r16) > off && r <= rune(r16[len(r16)-1].Hi) {
return is16(r16[off:], uint16(r))
}
r32 := rangeTab.R32
if len(r32) > 0 && r >= rune(r32[0].Lo) {
return is32(r32, uint32(r))
}
return false
}
// IsUpper reports whether the rune is an upper case letter.
func IsUpper(r rune) bool {
// See comment in IsGraphic.
if uint32(r) <= MaxLatin1 {
return properties[uint8(r)]&pLu != 0
}
return Is(Upper, r)
return isExcludingLatin(Upper, r)
}
// IsLower reports whether the rune is a lower case letter.
@ -163,7 +191,7 @@ func IsLower(r rune) bool {
if uint32(r) <= MaxLatin1 {
return properties[uint8(r)]&pLl != 0
}
return Is(Lower, r)
return isExcludingLatin(Lower, r)
}
// IsTitle reports whether the rune is a title case letter.
@ -171,7 +199,7 @@ func IsTitle(r rune) bool {
if r <= MaxLatin1 {
return false
}
return Is(Title, r)
return isExcludingLatin(Title, r)
}
// to maps the rune using the specified case mapping.

View File

@ -5,6 +5,10 @@
package unicode_test
import (
"flag"
"fmt"
"runtime"
"sort"
"testing"
. "unicode"
)
@ -427,3 +431,117 @@ func TestSimpleFold(t *testing.T) {
}
}
}
// Running 'go test -calibrate' runs the calibration to find a plausible
// cutoff point for linear search of a range list vs. binary search.
// We create a fake table and then time how long it takes to do a
// sequence of searches within that table, for all possible inputs
// relative to the ranges (something before all, in each, between each, after all).
// This assumes that all possible runes are equally likely.
// In practice most runes are ASCII so this is a conservative estimate
// of an effective cutoff value. In practice we could probably set it higher
// than what this function recommends.
var calibrate = flag.Bool("calibrate", false, "compute crossover for linear vs. binary search")
func TestCalibrate(t *testing.T) {
if !*calibrate {
return
}
if runtime.GOARCH == "amd64" {
fmt.Printf("warning: running calibration on %s\n", runtime.GOARCH)
}
// Find the point where binary search wins by more than 10%.
// The 10% bias gives linear search an edge when they're close,
// because on predominantly ASCII inputs linear search is even
// better than our benchmarks measure.
n := sort.Search(64, func(n int) bool {
tab := fakeTable(n)
blinear := func(b *testing.B) {
tab := tab
max := n*5 + 20
for i := 0; i < b.N; i++ {
for j := 0; j <= max; j++ {
linear(tab, uint16(j))
}
}
}
bbinary := func(b *testing.B) {
tab := tab
max := n*5 + 20
for i := 0; i < b.N; i++ {
for j := 0; j <= max; j++ {
binary(tab, uint16(j))
}
}
}
bmlinear := testing.Benchmark(blinear)
bmbinary := testing.Benchmark(bbinary)
fmt.Printf("n=%d: linear=%d binary=%d\n", n, bmlinear.NsPerOp(), bmbinary.NsPerOp())
return bmlinear.NsPerOp()*100 > bmbinary.NsPerOp()*110
})
fmt.Printf("calibration: linear cutoff = %d\n", n)
}
func fakeTable(n int) []Range16 {
var r16 []Range16
for i := 0; i < n; i++ {
r16 = append(r16, Range16{uint16(i*5 + 10), uint16(i*5 + 12), 1})
}
return r16
}
func linear(ranges []Range16, r uint16) bool {
for i := range ranges {
range_ := &ranges[i]
if r < range_.Lo {
return false
}
if r <= range_.Hi {
return (r-range_.Lo)%range_.Stride == 0
}
}
return false
}
func binary(ranges []Range16, r uint16) bool {
// binary search over ranges
lo := 0
hi := len(ranges)
for lo < hi {
m := lo + (hi-lo)/2
range_ := &ranges[m]
if range_.Lo <= r && r <= range_.Hi {
return (r-range_.Lo)%range_.Stride == 0
}
if r < range_.Lo {
hi = m
} else {
lo = m + 1
}
}
return false
}
func TestLatinOffset(t *testing.T) {
var maps = []map[string]*RangeTable{
Categories,
FoldCategory,
FoldScript,
Properties,
Scripts,
}
for _, m := range maps {
for name, tab := range m {
i := 0
for i < len(tab.R16) && tab.R16[i].Hi <= MaxLatin1 {
i++
}
if tab.LatinOffset != i {
t.Errorf("%s: LatinOffset=%d, want %d", name, tab.LatinOffset, i)
}
}
}
}

View File

@ -503,6 +503,7 @@ const format = "\t\t{0x%04x, 0x%04x, %d},\n"
func dumpRange(header string, inCategory Op) {
fmt.Print(header)
next := rune(0)
latinOffset := 0
fmt.Print("\tR16: []Range16{\n")
// one Range for each iteration
count := &range16Count
@ -546,11 +547,17 @@ func dumpRange(header string, inCategory Op) {
break
}
}
if uint32(hi) <= unicode.MaxLatin1 {
latinOffset++
}
size, count = printRange(uint32(lo), uint32(hi), uint32(stride), size, count)
// next range: start looking where this range ends
next = hi + 1
}
fmt.Print("\t},\n")
if latinOffset > 0 {
fmt.Printf("\tLatinOffset: %d,\n", latinOffset)
}
fmt.Print("}\n\n")
}
@ -760,14 +767,17 @@ func printScriptOrProperty(doProps bool) {
}
ndecl++
fmt.Printf("var _%s = &RangeTable {\n", name)
fmt.Print("\tR16: []Range16{\n")
ranges := foldAdjacent(table[name])
fmt.Print("\tR16: []Range16{\n")
size := 16
count := &range16Count
for _, s := range ranges {
size, count = printRange(s.Lo, s.Hi, s.Stride, size, count)
}
fmt.Print("\t},\n")
if off := findLatinOffset(ranges); off > 0 {
fmt.Printf("\tLatinOffset: %d,\n", off)
}
fmt.Print("}\n\n")
}
decl.Sort()
@ -779,6 +789,14 @@ func printScriptOrProperty(doProps bool) {
fmt.Print(")\n\n")
}
func findLatinOffset(ranges []unicode.Range32) int {
i := 0
for i < len(ranges) && ranges[i].Hi <= unicode.MaxLatin1 {
i++
}
return i
}
const (
CaseUpper = 1 << iota
CaseLower

View File

@ -71,6 +71,7 @@ var _C = &RangeTable{
{0xf0000, 0xffffd, 1},
{0x100000, 0x10fffd, 1},
},
LatinOffset: 2,
}
var _Cc = &RangeTable{
@ -78,6 +79,7 @@ var _Cc = &RangeTable{
{0x0001, 0x001f, 1},
{0x007f, 0x009f, 1},
},
LatinOffset: 2,
}
var _Cf = &RangeTable{
@ -536,6 +538,7 @@ var _L = &RangeTable{
{0x2b740, 0x2b81d, 1},
{0x2f800, 0x2fa1d, 1},
},
LatinOffset: 6,
}
var _Ll = &RangeTable{
@ -682,6 +685,7 @@ var _Ll = &RangeTable{
{0x1d7c4, 0x1d7c9, 1},
{0x1d7cb, 0x1d7cb, 1},
},
LatinOffset: 5,
}
var _Lm = &RangeTable{
@ -1186,6 +1190,7 @@ var _Lu = &RangeTable{
{0x1d790, 0x1d7a8, 1},
{0x1d7ca, 0x1d7ca, 1},
},
LatinOffset: 3,
}
var _M = &RangeTable{
@ -1769,6 +1774,7 @@ var _N = &RangeTable{
{0x1d7ce, 0x1d7ff, 1},
{0x1f100, 0x1f10a, 1},
},
LatinOffset: 4,
}
var _Nd = &RangeTable{
@ -1814,6 +1820,7 @@ var _Nd = &RangeTable{
{0x11066, 0x1106f, 1},
{0x1d7ce, 0x1d7ff, 1},
},
LatinOffset: 1,
}
var _Nl = &RangeTable{
@ -1879,6 +1886,7 @@ var _No = &RangeTable{
{0x1d360, 0x1d371, 1},
{0x1f100, 0x1f10a, 1},
},
LatinOffset: 3,
}
var _P = &RangeTable{
@ -2003,6 +2011,7 @@ var _P = &RangeTable{
{0x110be, 0x110c1, 1},
{0x12470, 0x12473, 1},
},
LatinOffset: 10,
}
var _Pc = &RangeTable{
@ -2053,6 +2062,7 @@ var _Pe = &RangeTable{
{0xff09, 0xff3d, 52},
{0xff5d, 0xff63, 3},
},
LatinOffset: 1,
}
var _Pf = &RangeTable{
@ -2194,6 +2204,7 @@ var _Po = &RangeTable{
{0x110be, 0x110c1, 1},
{0x12470, 0x12473, 1},
},
LatinOffset: 7,
}
var _Ps = &RangeTable{
@ -2222,6 +2233,7 @@ var _Ps = &RangeTable{
{0xff5b, 0xff5f, 4},
{0xff62, 0xff62, 1},
},
LatinOffset: 1,
}
var _S = &RangeTable{
@ -2409,6 +2421,7 @@ var _S = &RangeTable{
{0x1f680, 0x1f6c5, 1},
{0x1f700, 0x1f773, 1},
},
LatinOffset: 9,
}
var _Sc = &RangeTable{
@ -2425,6 +2438,7 @@ var _Sc = &RangeTable{
{0xffe0, 0xffe1, 1},
{0xffe5, 0xffe6, 1},
},
LatinOffset: 2,
}
var _Sk = &RangeTable{
@ -2452,6 +2466,7 @@ var _Sk = &RangeTable{
{0xff3e, 0xff40, 2},
{0xffe3, 0xffe3, 1},
},
LatinOffset: 3,
}
var _Sm = &RangeTable{
@ -2510,6 +2525,7 @@ var _Sm = &RangeTable{
{0x1d76f, 0x1d789, 26},
{0x1d7a9, 0x1d7c3, 26},
},
LatinOffset: 5,
}
var _So = &RangeTable{
@ -2666,6 +2682,7 @@ var _So = &RangeTable{
{0x1f680, 0x1f6c5, 1},
{0x1f700, 0x1f773, 1},
},
LatinOffset: 3,
}
var _Z = &RangeTable{
@ -2677,6 +2694,7 @@ var _Z = &RangeTable{
{0x202f, 0x205f, 48},
{0x3000, 0x3000, 1},
},
LatinOffset: 1,
}
var _Zl = &RangeTable{
@ -2699,6 +2717,7 @@ var _Zs = &RangeTable{
{0x202f, 0x205f, 48},
{0x3000, 0x3000, 1},
},
LatinOffset: 1,
}
// These variables have type *RangeTable.
@ -3179,6 +3198,7 @@ var _Common = &RangeTable{
{0xe0001, 0xe0001, 1},
{0xe0020, 0xe007f, 1},
},
LatinOffset: 7,
}
var _Coptic = &RangeTable{
@ -3649,6 +3669,7 @@ var _Latin = &RangeTable{
{0xff21, 0xff3a, 1},
{0xff41, 0xff5a, 1},
},
LatinOffset: 6,
}
var _Lepcha = &RangeTable{
@ -4199,6 +4220,7 @@ var _ASCII_Hex_Digit = &RangeTable{
{0x0041, 0x0046, 1},
{0x0061, 0x0066, 1},
},
LatinOffset: 3,
}
var _Bidi_Control = &RangeTable{
@ -4230,6 +4252,7 @@ var _Dash = &RangeTable{
{0xfe63, 0xfe63, 1},
{0xff0d, 0xff0d, 1},
},
LatinOffset: 1,
}
var _Deprecated = &RangeTable{
@ -4370,6 +4393,7 @@ var _Diacritic = &RangeTable{
{0x1d185, 0x1d18b, 1},
{0x1d1aa, 0x1d1ad, 1},
},
LatinOffset: 6,
}
var _Extender = &RangeTable{
@ -4395,6 +4419,7 @@ var _Extender = &RangeTable{
{0xaadd, 0xaadd, 1},
{0xff70, 0xff70, 1},
},
LatinOffset: 1,
}
var _Hex_Digit = &RangeTable{
@ -4406,6 +4431,7 @@ var _Hex_Digit = &RangeTable{
{0xff21, 0xff26, 1},
{0xff41, 0xff46, 1},
},
LatinOffset: 3,
}
var _Hyphen = &RangeTable{
@ -4421,6 +4447,7 @@ var _Hyphen = &RangeTable{
{0xff0d, 0xff0d, 1},
{0xff65, 0xff65, 1},
},
LatinOffset: 2,
}
var _IDS_Binary_Operator = &RangeTable{
@ -4695,6 +4722,7 @@ var _Other_ID_Continue = &RangeTable{
{0x1369, 0x1371, 1},
{0x19da, 0x19da, 1},
},
LatinOffset: 1,
}
var _Other_ID_Start = &RangeTable{
@ -4828,6 +4856,7 @@ var _Other_Math = &RangeTable{
{0x1d7c4, 0x1d7cb, 1},
{0x1d7ce, 0x1d7ff, 1},
},
LatinOffset: 1,
}
var _Other_Uppercase = &RangeTable{
@ -4868,6 +4897,7 @@ var _Pattern_Syntax = &RangeTable{
{0xfd3e, 0xfd3f, 1},
{0xfe45, 0xfe46, 1},
},
LatinOffset: 15,
}
var _Pattern_White_Space = &RangeTable{
@ -4878,6 +4908,7 @@ var _Pattern_White_Space = &RangeTable{
{0x200e, 0x200f, 1},
{0x2028, 0x2029, 1},
},
LatinOffset: 3,
}
var _Quotation_Mark = &RangeTable{
@ -4895,6 +4926,7 @@ var _Quotation_Mark = &RangeTable{
{0xff07, 0xff07, 1},
{0xff62, 0xff63, 1},
},
LatinOffset: 4,
}
var _Radical = &RangeTable{
@ -4957,6 +4989,7 @@ var _STerm = &RangeTable{
{0x11047, 0x11048, 1},
{0x110be, 0x110c1, 1},
},
LatinOffset: 3,
}
var _Soft_Dotted = &RangeTable{
@ -4995,6 +5028,7 @@ var _Soft_Dotted = &RangeTable{
{0x1d65e, 0x1d65f, 1},
{0x1d692, 0x1d693, 1},
},
LatinOffset: 1,
}
var _Terminal_Punctuation = &RangeTable{
@ -5069,6 +5103,7 @@ var _Terminal_Punctuation = &RangeTable{
{0x110be, 0x110c1, 1},
{0x12470, 0x12473, 1},
},
LatinOffset: 5,
}
var _Unified_Ideograph = &RangeTable{
@ -5114,6 +5149,7 @@ var _White_Space = &RangeTable{
{0x205f, 0x205f, 1},
{0x3000, 0x3000, 1},
},
LatinOffset: 4,
}
// These variables have type *RangeTable.
@ -5887,6 +5923,7 @@ var foldLl = &RangeTable{
R32: []Range32{
{0x10400, 0x10427, 1},
},
LatinOffset: 3,
}
var foldLt = &RangeTable{
@ -6001,6 +6038,7 @@ var foldLu = &RangeTable{
R32: []Range32{
{0x10428, 0x1044f, 1},
},
LatinOffset: 4,
}
var foldM = &RangeTable{