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/#1-8 276ns ± 3% 249ns ± 0% -9.62% (p=0.000 n=10+7) QueryEscape/#2-8 176ns ± 2% 155ns ± 3% -12.21% (p=0.000 n=10+10) QueryEscape/#3-8 388ns ± 1% 362ns ± 0% -6.55% (p=0.000 n=10+8) QueryEscape/#4-8 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/#1-8 276ns ± 2% 260ns ± 0% -6.01% (p=0.000 n=10+10) PathEscape/#2-8 175ns ± 0% 153ns ± 0% -12.53% (p=0.000 n=8+10) PathEscape/#3-8 389ns ± 2% 361ns ± 0% -7.21% (p=0.000 n=10+9) PathEscape/#4-8 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/#1-8 128B ± 0% 64B ± 0% -50.00% (p=0.000 n=10+10) QueryEscape/#2-8 64.0B ± 0% 32.0B ± 0% -50.00% (p=0.000 n=10+10) QueryEscape/#3-8 128B ± 0% 64B ± 0% -50.00% (p=0.000 n=10+10) QueryEscape/#4-8 832B ± 0% 832B ± 0% ~ (all equal) PathEscape/#00-8 32.0B ± 0% 16.0B ± 0% -50.00% (p=0.000 n=10+10) PathEscape/#1-8 128B ± 0% 64B ± 0% -50.00% (p=0.000 n=10+10) PathEscape/#2-8 64.0B ± 0% 32.0B ± 0% -50.00% (p=0.000 n=10+10) PathEscape/#3-8 128B ± 0% 64B ± 0% -50.00% (p=0.000 n=10+10) PathEscape/#4-8 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/#1-8 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=10+10) QueryEscape/#2-8 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=10+10) QueryEscape/#3-8 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=10+10) QueryEscape/#4-8 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/#1-8 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=10+10) PathEscape/#2-8 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=10+10) PathEscape/#3-8 2.00 ± 0% 1.00 ± 0% -50.00% (p=0.000 n=10+10) PathEscape/#4-8 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>
golang · Sep 11, 2018 · 95a11c7 · 95a11c7
1 parent 0f72e79
commit 95a11c7
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Showing 2 changed files with 123 additions and 1 deletion.
diff --git a/src/net/url/url.go b/src/net/url/url.go
@@ -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]; {

diff --git a/src/net/url/url_test.go b/src/net/url/url_test.go
@@ -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)
+			}
+
+		})
+	}
+}