From: Martin Möhrmann Date: Sat, 12 Aug 2017 08:20:30 +0000 (+0200) Subject: bytes: speed up Fields and FieldsFunc X-Git-Tag: go1.10beta1~1592 X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=7df29b50b2d7fd9abcd2a070df407db57f3f79a6;p=gostls13.git bytes: speed up Fields and FieldsFunc Applies the optimizations from golang.org/cl/42810 and golang.org/cl/37959 done to the strings package to the bytes package. name old time/op new time/op delta Fields/ASCII/16 417ns ± 4% 118ns ± 3% -71.65% (p=0.000 n=10+10) Fields/ASCII/256 5.95µs ± 3% 0.88µs ± 0% -85.23% (p=0.000 n=10+7) Fields/ASCII/4096 92.3µs ± 1% 12.8µs ± 2% -86.13% (p=0.000 n=10+10) Fields/ASCII/65536 1.49ms ± 1% 0.25ms ± 1% -83.14% (p=0.000 n=10+10) Fields/ASCII/1048576 25.0ms ± 1% 6.5ms ± 2% -74.04% (p=0.000 n=10+10) Fields/Mixed/16 406ns ± 1% 222ns ± 1% -45.24% (p=0.000 n=10+9) Fields/Mixed/256 5.78µs ± 1% 2.27µs ± 1% -60.73% (p=0.000 n=9+10) Fields/Mixed/4096 97.9µs ± 1% 40.5µs ± 3% -58.66% (p=0.000 n=10+10) Fields/Mixed/65536 1.58ms ± 1% 0.69ms ± 1% -56.58% (p=0.000 n=10+10) Fields/Mixed/1048576 26.6ms ± 1% 12.6ms ± 2% -52.44% (p=0.000 n=9+10) FieldsFunc/ASCII/16 395ns ± 1% 188ns ± 1% -52.34% (p=0.000 n=10+10) FieldsFunc/ASCII/256 5.90µs ± 1% 2.00µs ± 1% -66.06% (p=0.000 n=10+10) FieldsFunc/ASCII/4096 92.5µs ± 1% 33.0µs ± 1% -64.34% (p=0.000 n=10+9) FieldsFunc/ASCII/65536 1.48ms ± 1% 0.54ms ± 1% -63.38% (p=0.000 n=10+9) FieldsFunc/ASCII/1048576 25.1ms ± 1% 10.5ms ± 3% -58.24% (p=0.000 n=10+10) FieldsFunc/Mixed/16 401ns ± 1% 205ns ± 2% -48.87% (p=0.000 n=10+10) FieldsFunc/Mixed/256 5.70µs ± 1% 1.98µs ± 1% -65.28% (p=0.000 n=10+10) FieldsFunc/Mixed/4096 97.5µs ± 1% 35.4µs ± 1% -63.65% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 1.57ms ± 1% 0.61ms ± 1% -61.20% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 26.5ms ± 1% 11.4ms ± 2% -56.84% (p=0.000 n=10+10) name old speed new speed delta Fields/ASCII/16 38.4MB/s ± 4% 134.9MB/s ± 3% +251.55% (p=0.000 n=10+10) Fields/ASCII/256 43.0MB/s ± 3% 290.6MB/s ± 1% +575.97% (p=0.000 n=10+8) Fields/ASCII/4096 44.4MB/s ± 1% 320.0MB/s ± 2% +620.90% (p=0.000 n=10+10) Fields/ASCII/65536 44.0MB/s ± 1% 260.7MB/s ± 1% +493.15% (p=0.000 n=10+10) Fields/ASCII/1048576 42.0MB/s ± 1% 161.6MB/s ± 2% +285.21% (p=0.000 n=10+10) Fields/Mixed/16 39.4MB/s ± 1% 71.7MB/s ± 1% +82.20% (p=0.000 n=10+10) Fields/Mixed/256 44.3MB/s ± 1% 112.8MB/s ± 1% +154.64% (p=0.000 n=9+10) Fields/Mixed/4096 41.9MB/s ± 1% 101.2MB/s ± 3% +141.92% (p=0.000 n=10+10) Fields/Mixed/65536 41.5MB/s ± 1% 95.5MB/s ± 1% +130.29% (p=0.000 n=10+10) Fields/Mixed/1048576 39.4MB/s ± 1% 82.9MB/s ± 2% +110.28% (p=0.000 n=9+10) FieldsFunc/ASCII/16 40.5MB/s ± 1% 84.9MB/s ± 2% +109.80% (p=0.000 n=10+10) FieldsFunc/ASCII/256 43.4MB/s ± 1% 127.9MB/s ± 1% +194.58% (p=0.000 n=10+10) FieldsFunc/ASCII/4096 44.3MB/s ± 1% 124.2MB/s ± 1% +180.44% (p=0.000 n=10+9) FieldsFunc/ASCII/65536 44.2MB/s ± 1% 120.6MB/s ± 1% +173.06% (p=0.000 n=10+9) FieldsFunc/ASCII/1048576 41.8MB/s ± 1% 100.2MB/s ± 3% +139.53% (p=0.000 n=10+10) FieldsFunc/Mixed/16 39.8MB/s ± 1% 77.8MB/s ± 2% +95.46% (p=0.000 n=10+10) FieldsFunc/Mixed/256 44.9MB/s ± 1% 129.4MB/s ± 1% +187.97% (p=0.000 n=10+10) FieldsFunc/Mixed/4096 42.0MB/s ± 1% 115.6MB/s ± 1% +175.08% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 41.6MB/s ± 1% 107.3MB/s ± 1% +157.75% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 39.6MB/s ± 1% 91.8MB/s ± 2% +131.72% (p=0.000 n=10+10) name old alloc/op new alloc/op delta Fields/ASCII/16 80.0B ± 0% 80.0B ± 0% ~ (all equal) Fields/ASCII/256 768B ± 0% 768B ± 0% ~ (all equal) Fields/ASCII/4096 9.47kB ± 0% 9.47kB ± 0% ~ (all equal) Fields/ASCII/65536 147kB ± 0% 147kB ± 0% ~ (all equal) Fields/ASCII/1048576 2.27MB ± 0% 2.27MB ± 0% ~ (all equal) Fields/Mixed/16 96.0B ± 0% 96.0B ± 0% ~ (all equal) Fields/Mixed/256 768B ± 0% 768B ± 0% ~ (all equal) Fields/Mixed/4096 9.47kB ± 0% 24.83kB ± 0% +162.16% (p=0.000 n=10+10) Fields/Mixed/65536 147kB ± 0% 497kB ± 0% +237.24% (p=0.000 n=10+10) Fields/Mixed/1048576 2.26MB ± 0% 9.61MB ± 0% +324.89% (p=0.000 n=10+10) FieldsFunc/ASCII/16 80.0B ± 0% 80.0B ± 0% ~ (all equal) FieldsFunc/ASCII/256 768B ± 0% 768B ± 0% ~ (all equal) FieldsFunc/ASCII/4096 9.47kB ± 0% 24.83kB ± 0% +162.16% (p=0.000 n=10+10) FieldsFunc/ASCII/65536 147kB ± 0% 497kB ± 0% +237.24% (p=0.000 n=10+10) FieldsFunc/ASCII/1048576 2.27MB ± 0% 9.61MB ± 0% +323.72% (p=0.000 n=10+10) FieldsFunc/Mixed/16 96.0B ± 0% 96.0B ± 0% ~ (all equal) FieldsFunc/Mixed/256 768B ± 0% 768B ± 0% ~ (all equal) FieldsFunc/Mixed/4096 9.47kB ± 0% 24.83kB ± 0% +162.16% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 147kB ± 0% 497kB ± 0% +237.24% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 2.26MB ± 0% 9.61MB ± 0% +324.89% (p=0.000 n=10+10) name old allocs/op new allocs/op delta Fields/ASCII/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/4096 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/65536 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/ASCII/1048576 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/Mixed/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/Mixed/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) Fields/Mixed/4096 1.00 ± 0% 5.00 ± 0% +400.00% (p=0.000 n=10+10) Fields/Mixed/65536 1.00 ± 0% 12.00 ± 0% +1100.00% (p=0.000 n=10+10) Fields/Mixed/1048576 1.00 ± 0% 24.00 ± 0% +2300.00% (p=0.000 n=10+10) FieldsFunc/ASCII/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/ASCII/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/ASCII/4096 1.00 ± 0% 5.00 ± 0% +400.00% (p=0.000 n=10+10) FieldsFunc/ASCII/65536 1.00 ± 0% 12.00 ± 0% +1100.00% (p=0.000 n=10+10) FieldsFunc/ASCII/1048576 1.00 ± 0% 24.00 ± 0% +2300.00% (p=0.000 n=10+10) FieldsFunc/Mixed/16 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/Mixed/256 1.00 ± 0% 1.00 ± 0% ~ (all equal) FieldsFunc/Mixed/4096 1.00 ± 0% 5.00 ± 0% +400.00% (p=0.000 n=10+10) FieldsFunc/Mixed/65536 1.00 ± 0% 12.00 ± 0% +1100.00% (p=0.000 n=10+10) FieldsFunc/Mixed/1048576 1.00 ± 0% 24.00 ± 0% +2300.00% (p=0.000 n=10+10) Change-Id: If1926782decc2f60d3b4b8c41c2ce7d8bdedfd8f Reviewed-on: https://go-review.googlesource.com/55131 Run-TryBot: Martin Möhrmann TryBot-Result: Gobot Gobot Reviewed-by: Joe Tsai --- diff --git a/src/bytes/bytes.go b/src/bytes/bytes.go index 7c878af688..457e149410 100644 --- a/src/bytes/bytes.go +++ b/src/bytes/bytes.go @@ -265,9 +265,57 @@ func SplitAfter(s, sep []byte) [][]byte { return genSplit(s, sep, len(sep), -1) } +var asciiSpace = [256]uint8{'\t': 1, '\n': 1, '\v': 1, '\f': 1, '\r': 1, ' ': 1} + // Fields splits the slice s around each instance of one or more consecutive white space -// characters, returning a slice of subslices of s or an empty list if s contains only white space. +// characters, as defined by unicode.IsSpace, returning a slice of subslices of s or an +// empty slice if s contains only white space. func Fields(s []byte) [][]byte { + // First count the fields. + // This is an exact count if s is ASCII, otherwise it is an approximation. + n := 0 + wasSpace := 1 + // setBits is used to track which bits are set in the bytes of s. + setBits := uint8(0) + for i := 0; i < len(s); i++ { + r := s[i] + setBits |= r + isSpace := int(asciiSpace[r]) + n += wasSpace & ^isSpace + wasSpace = isSpace + } + + if setBits < utf8.RuneSelf { // ASCII fast path + a := make([][]byte, n) + na := 0 + fieldStart := 0 + i := 0 + // Skip spaces in the front of the input. + for i < len(s) && asciiSpace[s[i]] != 0 { + i++ + } + fieldStart = i + for i < len(s) { + if asciiSpace[s[i]] == 0 { + i++ + continue + } + a[na] = s[fieldStart:i] + na++ + i++ + // Skip spaces in between fields. + for i < len(s) && asciiSpace[s[i]] != 0 { + i++ + } + fieldStart = i + } + if fieldStart < len(s) { // Last field might end at EOF. + a[na] = s[fieldStart:] + } + return a + } + + // Some runes in the input slice are not ASCII. return FieldsFunc(s, unicode.IsSpace) } @@ -278,39 +326,49 @@ func Fields(s []byte) [][]byte { // FieldsFunc makes no guarantees about the order in which it calls f(c). // If f does not return consistent results for a given c, FieldsFunc may crash. func FieldsFunc(s []byte, f func(rune) bool) [][]byte { - n := 0 - inField := false - for i := 0; i < len(s); { - r, size := utf8.DecodeRune(s[i:]) - wasInField := inField - inField = !f(r) - if inField && !wasInField { - n++ - } - i += size + // A span is used to record a slice of s of the form s[start:end]. + // The start index is inclusive and the end index is exclusive. + type span struct { + start int + end int } + spans := make([]span, 0, 32) - a := make([][]byte, n) - na := 0 - fieldStart := -1 - for i := 0; i <= len(s) && na < n; { - r, size := utf8.DecodeRune(s[i:]) - if fieldStart < 0 && size > 0 && !f(r) { - fieldStart = i - i += size - continue - } - if fieldStart >= 0 && (size == 0 || f(r)) { - a[na] = s[fieldStart:i] - na++ - fieldStart = -1 + // Find the field start and end indices. + wasField := false + fromIndex := 0 + for i := 0; i < len(s); { + size := 1 + r := rune(s[i]) + if r >= utf8.RuneSelf { + r, size = utf8.DecodeRune(s[i:]) } - if size == 0 { - break + if f(r) { + if wasField { + spans = append(spans, span{start: fromIndex, end: i}) + wasField = false + } + } else { + if !wasField { + fromIndex = i + wasField = true + } } i += size } - return a[0:na] + + // Last field might end at EOF. + if wasField { + spans = append(spans, span{fromIndex, len(s)}) + } + + // Create subslices from recorded field indices. + a := make([][]byte, len(spans)) + for i, span := range spans { + a[i] = s[span.start:span.end] + } + + return a } // Join concatenates the elements of s to create a new byte slice. The separator diff --git a/src/bytes/bytes_test.go b/src/bytes/bytes_test.go index ca0cdbb7c9..db28497e39 100644 --- a/src/bytes/bytes_test.go +++ b/src/bytes/bytes_test.go @@ -1502,19 +1502,58 @@ var makeFieldsInput = func() []byte { return x } -var fieldsInput = makeFieldsInput() +var makeFieldsInputASCII = func() []byte { + x := make([]byte, 1<<20) + // Input is ~10% space, rest ASCII non-space. + for i := range x { + if rand.Intn(10) == 0 { + x[i] = ' ' + } else { + x[i] = 'x' + } + } + return x +} + +var bytesdata = []struct { + name string + data []byte +}{ + {"ASCII", makeFieldsInputASCII()}, + {"Mixed", makeFieldsInput()}, +} func BenchmarkFields(b *testing.B) { - b.SetBytes(int64(len(fieldsInput))) - for i := 0; i < b.N; i++ { - Fields(fieldsInput) + for _, sd := range bytesdata { + b.Run(sd.name, func(b *testing.B) { + for j := 1 << 4; j <= 1<<20; j <<= 4 { + b.Run(fmt.Sprintf("%d", j), func(b *testing.B) { + b.ReportAllocs() + b.SetBytes(int64(j)) + data := sd.data[:j] + for i := 0; i < b.N; i++ { + Fields(data) + } + }) + } + }) } } func BenchmarkFieldsFunc(b *testing.B) { - b.SetBytes(int64(len(fieldsInput))) - for i := 0; i < b.N; i++ { - FieldsFunc(fieldsInput, unicode.IsSpace) + for _, sd := range bytesdata { + b.Run(sd.name, func(b *testing.B) { + for j := 1 << 4; j <= 1<<20; j <<= 4 { + b.Run(fmt.Sprintf("%d", j), func(b *testing.B) { + b.ReportAllocs() + b.SetBytes(int64(j)) + data := sd.data[:j] + for i := 0; i < b.N; i++ { + FieldsFunc(data, unicode.IsSpace) + } + }) + } + }) } }