net/url: remove an allocation for short strings in escape

Use a 64 byte array to avoid an allocation on the assumption that
most url escaping is performed on short strings. Also adds a fast
path for escaping strings whose only replacements are spaces which
is common in query components.

Adds benchmarks for QueryEscape, PathEscape, QueryUnescape and
PathUnescape but no optimizations are include for the unescape functions
so I don't include those benchmark results here.

Reduces allocations by 10% in the existing String benchmark with a
modest performance increase.

name               old time/op    new time/op    delta
QueryEscape/#00-8    64.6ns ± 1%    43.8ns ± 0%  -32.14%  (p=0.000 n=9+9)
QueryEscape/#01-8     276ns ± 3%     249ns ± 0%   -9.62%  (p=0.000 n=10+7)
QueryEscape/#02-8     176ns ± 2%     155ns ± 3%  -12.21%  (p=0.000 n=10+10)
QueryEscape/#03-8     388ns ± 1%     362ns ± 0%   -6.55%  (p=0.000 n=10+8)
QueryEscape/#04-8    2.32µs ± 2%    2.27µs ± 2%   -2.26%  (p=0.001 n=10+10)
PathEscape/#00-8     78.0ns ± 3%    63.4ns ± 1%  -18.69%  (p=0.000 n=10+10)
PathEscape/#01-8      276ns ± 2%     260ns ± 0%   -6.01%  (p=0.000 n=10+10)
PathEscape/#02-8      175ns ± 0%     153ns ± 0%  -12.53%  (p=0.000 n=8+10)
PathEscape/#03-8      389ns ± 2%     361ns ± 0%   -7.21%  (p=0.000 n=10+9)
PathEscape/#04-8     2.30µs ± 2%    2.27µs ± 1%   -1.33%  (p=0.001 n=9+10)
String-8             3.56µs ± 4%    3.42µs ± 7%   -4.00%  (p=0.003 n=10+10)

name               old alloc/op   new alloc/op   delta
QueryEscape/#00-8     16.0B ± 0%      8.0B ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#01-8      128B ± 0%       64B ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#02-8     64.0B ± 0%     32.0B ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#03-8      128B ± 0%       64B ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#04-8      832B ± 0%      832B ± 0%     ~     (all equal)
PathEscape/#00-8      32.0B ± 0%     16.0B ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#01-8       128B ± 0%       64B ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#02-8      64.0B ± 0%     32.0B ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#03-8       128B ± 0%       64B ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#04-8       704B ± 0%      704B ± 0%     ~     (all equal)
String-8             1.84kB ± 0%    1.66kB ± 0%   -9.57%  (p=0.000 n=10+10)

name               old allocs/op  new allocs/op  delta
QueryEscape/#00-8      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#01-8      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#02-8      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#03-8      2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
QueryEscape/#04-8      2.00 ± 0%      2.00 ± 0%     ~     (all equal)
PathEscape/#00-8       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#01-8       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#02-8       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#03-8       2.00 ± 0%      1.00 ± 0%  -50.00%  (p=0.000 n=10+10)
PathEscape/#04-8       2.00 ± 0%      2.00 ± 0%     ~     (all equal)
String-8               69.0 ± 0%      61.0 ± 0%  -11.59%  (p=0.000 n=10+10)

Updates #17860

Change-Id: I45c5e9d40b242f874c61f6ccc73bf94c494bb868
Reviewed-on: https://go-review.googlesource.com/134296
Run-TryBot: Brad Fitzpatrick <bradfitz@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>
This commit is contained in:
Ian Davis 2018-09-10 12:13:09 +01:00 committed by Brad Fitzpatrick
parent 0f72e79856
commit 95a11c7381
2 changed files with 123 additions and 1 deletions

View File

@ -304,7 +304,26 @@ func escape(s string, mode encoding) string {
return s
}
t := make([]byte, len(s)+2*hexCount)
var buf [64]byte
var t []byte
required := len(s) + 2*hexCount
if required <= len(buf) {
t = buf[:required]
} else {
t = make([]byte, required)
}
if hexCount == 0 {
copy(t, s)
for i := 0; i < len(s); i++ {
if s[i] == ' ' {
t[i] = '+'
}
}
return string(t)
}
j := 0
for i := 0; i < len(s); i++ {
switch c := s[i]; {

View File

@ -1754,3 +1754,106 @@ func TestInvalidUserPassword(t *testing.T) {
t.Errorf("error = %q; want substring %q", got, wantsub)
}
}
var escapeBenchmarks = []struct {
unescaped string
query string
path string
}{
{
unescaped: "one two",
query: "one+two",
path: "one%20two",
},
{
unescaped: "Фотки собак",
query: "%D0%A4%D0%BE%D1%82%D0%BA%D0%B8+%D1%81%D0%BE%D0%B1%D0%B0%D0%BA",
path: "%D0%A4%D0%BE%D1%82%D0%BA%D0%B8%20%D1%81%D0%BE%D0%B1%D0%B0%D0%BA",
},
{
unescaped: "shortrun(break)shortrun",
query: "shortrun%28break%29shortrun",
path: "shortrun%28break%29shortrun",
},
{
unescaped: "longerrunofcharacters(break)anotherlongerrunofcharacters",
query: "longerrunofcharacters%28break%29anotherlongerrunofcharacters",
path: "longerrunofcharacters%28break%29anotherlongerrunofcharacters",
},
{
unescaped: strings.Repeat("padded/with+various%characters?that=need$some@escaping+paddedsowebreak/256bytes", 4),
query: strings.Repeat("padded%2Fwith%2Bvarious%25characters%3Fthat%3Dneed%24some%40escaping%2Bpaddedsowebreak%2F256bytes", 4),
path: strings.Repeat("padded%2Fwith+various%25characters%3Fthat=need$some@escaping+paddedsowebreak%2F256bytes", 4),
},
}
func BenchmarkQueryEscape(b *testing.B) {
for _, tc := range escapeBenchmarks {
b.Run("", func(b *testing.B) {
b.ReportAllocs()
var g string
for i := 0; i < b.N; i++ {
g = QueryEscape(tc.unescaped)
}
b.StopTimer()
if g != tc.query {
b.Errorf("QueryEscape(%q) == %q, want %q", tc.unescaped, g, tc.query)
}
})
}
}
func BenchmarkPathEscape(b *testing.B) {
for _, tc := range escapeBenchmarks {
b.Run("", func(b *testing.B) {
b.ReportAllocs()
var g string
for i := 0; i < b.N; i++ {
g = PathEscape(tc.unescaped)
}
b.StopTimer()
if g != tc.path {
b.Errorf("PathEscape(%q) == %q, want %q", tc.unescaped, g, tc.path)
}
})
}
}
func BenchmarkQueryUnescape(b *testing.B) {
for _, tc := range escapeBenchmarks {
b.Run("", func(b *testing.B) {
b.ReportAllocs()
var g string
for i := 0; i < b.N; i++ {
g, _ = QueryUnescape(tc.query)
}
b.StopTimer()
if g != tc.unescaped {
b.Errorf("QueryUnescape(%q) == %q, want %q", tc.query, g, tc.unescaped)
}
})
}
}
func BenchmarkPathUnescape(b *testing.B) {
for _, tc := range escapeBenchmarks {
b.Run("", func(b *testing.B) {
b.ReportAllocs()
var g string
for i := 0; i < b.N; i++ {
g, _ = PathUnescape(tc.path)
}
b.StopTimer()
if g != tc.unescaped {
b.Errorf("PathUnescape(%q) == %q, want %q", tc.path, g, tc.unescaped)
}
})
}
}