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Author SHA1 Message Date
Olivier Poitrey fde564e937 Optimize JSON encoding even further
Last optimization was for JSON string with no character to encode. This
version focuses on strings with some chars to encode, trying to apply
the same trick for substrings that do not need encoding.

benchmark                old ns/op     new ns/op    delta
.../NoEncoding-8         60.2          51.3         -14.78%
.../EncodingFirst-8      140           116          -17.14%
.../EncodingMiddle-8     112           86.4         -22.86%
.../EncodingLast-8       62.8          61.1         -2.71%
.../MultiBytesFirst-8    164           129          -21.34%
.../MultiBytesMiddle-8   133           96.9         -27.14%
.../MultiBytesLast-8     81.9          73.5         -10.26%
2017-06-25 01:30:02 -07:00
Olivier Poitrey 274f2e4c61 Add some json encoder benchmarks 2017-06-24 18:30:15 -07:00
3 changed files with 99 additions and 48 deletions

View File

@ -255,11 +255,11 @@ Some settings can be changed and will by applied to all loggers:
All operations are allocation free (those numbers *include* JSON encoding):
```
BenchmarkLogEmpty-8 100000000 19.1 ns/op 0 B/op 0 allocs/op
BenchmarkDisabled-8 500000000 4.07 ns/op 0 B/op 0 allocs/op
BenchmarkInfo-8 30000000 46.3 ns/op 0 B/op 0 allocs/op
BenchmarkContextFields-8 30000000 47.1 ns/op 0 B/op 0 allocs/op
BenchmarkLogFields-8 10000000 186 ns/op 0 B/op 0 allocs/op
BenchmarkLogEmpty-8 100000000 19.1 ns/op 0 B/op 0 allocs/op
BenchmarkDisabled-8 500000000 4.07 ns/op 0 B/op 0 allocs/op
BenchmarkInfo-8 30000000 42.5 ns/op 0 B/op 0 allocs/op
BenchmarkContextFields-8 30000000 44.9 ns/op 0 B/op 0 allocs/op
BenchmarkLogFields-8 10000000 184 ns/op 0 B/op 0 allocs/op
```
Using Uber's zap [comparison benchmark](https://github.com/uber-go/zap#performance):

106
json.go
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@ -21,48 +21,10 @@ func appendJSONString(dst []byte, s string) []byte {
// Check if the character needs encoding. Control characters, slashes,
// and the double quote need json encoding. Bytes above the ascii
// boundary needs utf8 encoding.
if s[i] < ' ' || s[i] == '\\' || s[i] == '"' || s[i] > 126 {
// We encountered a character that needs to be encoded. Let's
// append the previous simple characters to the byte slice
// and switch our operation to read and encode the remainder
// characters byte-by-byte.
dst = append(dst, s[:i]...)
for i < len(s) {
if b := s[i]; b < utf8.RuneSelf {
switch b {
case '"', '\\':
dst = append(dst, '\\', b)
case '\b':
dst = append(dst, '\\', 'b')
case '\f':
dst = append(dst, '\\', 'f')
case '\n':
dst = append(dst, '\\', 'n')
case '\r':
dst = append(dst, '\\', 'r')
case '\t':
dst = append(dst, '\\', 't')
default:
if b >= 0x20 {
dst = append(dst, b)
} else {
dst = append(dst, '\\', 'u', '0', '0',
hex[b>>4], hex[b&0xF])
}
}
i++
continue
}
r, size := utf8.DecodeRuneInString(s[i:])
if r == utf8.RuneError && size == 1 {
dst = append(dst, `\ufffd`...)
i++
continue
}
dst = append(dst, s[i:i+size]...)
i += size
}
// End with a double quote
if s[i] < 0x20 || s[i] > 0x7e || s[i] == '\\' || s[i] == '"' {
// We encountered a character that needs to be encoded. Switch
// to complex version of the algorithm.
dst = appendJSONStringComplex(dst, s, i)
return append(dst, '"')
}
}
@ -72,3 +34,63 @@ func appendJSONString(dst []byte, s string) []byte {
// End with a double quote
return append(dst, '"')
}
// appendJSONStringComplex is used by appendJSONString to take over an in
// progress JSON string encoding that encountered a character that needs
// to be encoded.
func appendJSONStringComplex(dst []byte, s string, i int) []byte {
start := 0
for i < len(s) {
b := s[i]
if b >= utf8.RuneSelf {
r, size := utf8.DecodeRuneInString(s[i:])
if r == utf8.RuneError && size == 1 {
// In case of error, first append previous simple characters to
// the byte slice if any and append a remplacement character code
// in place of the invalid sequence.
if start < i {
dst = append(dst, s[start:i]...)
}
dst = append(dst, `\ufffd`...)
i += size
start = i
continue
}
i += size
continue
}
if b >= 0x20 && b <= 0x7e && b != '\\' && b != '"' {
i++
continue
}
// We encountered a character that needs to be encoded.
// Let's append the previous simple characters to the byte slice
// and switch our operation to read and encode the remainder
// characters byte-by-byte.
if start < i {
dst = append(dst, s[start:i]...)
}
switch b {
case '"', '\\':
dst = append(dst, '\\', b)
case '\b':
dst = append(dst, '\\', 'b')
case '\f':
dst = append(dst, '\\', 'f')
case '\n':
dst = append(dst, '\\', 'n')
case '\r':
dst = append(dst, '\\', 'r')
case '\t':
dst = append(dst, '\\', 't')
default:
dst = append(dst, '\\', 'u', '0', '0', hex[b>>4], hex[b&0xF])
}
i++
start = i
}
if start < len(s) {
dst = append(dst, s[start:]...)
}
return dst
}

View File

@ -1,12 +1,15 @@
package zerolog
import "testing"
import (
"testing"
)
func TestAppendJSONString(t *testing.T) {
encodeStringTests := []struct {
in string
out string
}{
{"", `""`},
{"\\", `"\\"`},
{"\x00", `"\u0000"`},
{"\x01", `"\u0001"`},
@ -40,7 +43,13 @@ func TestAppendJSONString(t *testing.T) {
{"\x1d", `"\u001d"`},
{"\x1e", `"\u001e"`},
{"\x1f", `"\u001f"`},
{"✭", `"✭"`},
{"foo\xc2\x7fbar", `"foo\ufffd\u007fbar"`}, // invalid sequence
{"ascii", `"ascii"`},
{"\"a", `"\"a"`},
{"\x1fa", `"\u001fa"`},
{"foo\"bar\"baz", `"foo\"bar\"baz"`},
{"\x1ffoo\x1fbar\x1fbaz", `"\u001ffoo\u001fbar\u001fbaz"`},
{"emoji \u2764\ufe0f!", `"emoji ❤️!"`},
}
@ -51,3 +60,23 @@ func TestAppendJSONString(t *testing.T) {
}
}
}
func BenchmarkAppendJSONString(b *testing.B) {
tests := map[string]string{
"NoEncoding": `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
"EncodingFirst": `"aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
"EncodingMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa"aaaaaaaaaaaaaaaaaaaaaaaa`,
"EncodingLast": `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa"`,
"MultiBytesFirst": `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa`,
"MultiBytesMiddle": `aaaaaaaaaaaaaaaaaaaaaaaaa❤aaaaaaaaaaaaaaaaaaaaaaaa`,
"MultiBytesLast": `aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa❤`,
}
for name, str := range tests {
b.Run(name, func(b *testing.B) {
buf := make([]byte, 0, 100)
for i := 0; i < b.N; i++ {
_ = appendJSONString(buf, str)
}
})
}
}