From 4b4f222a0dd8765e5b493d458fa352ea22045575 Mon Sep 17 00:00:00 2001 From: Ben Hoyt Date: Thu, 6 Dec 2018 08:53:29 -0500 Subject: bytes, strings: speed up TrimSpace 4-5x for common ASCII cases MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This change adds a fast path for ASCII strings to both strings.TrimSpace and bytes.TrimSpace. It doesn't slow down the non-ASCII path much, if at all. I added benchmarks for strings.TrimSpace as it didn't have any, and I fleshed out the benchmarks for bytes.TrimSpace as it just had one case (for ASCII). The benchmarks (and the code!) are now the same between the two versions. Below are the benchmark results: strings.TrimSpace: name old time/op new time/op delta TrimSpace/NoTrim-8 18.6ns ± 0% 3.8ns ± 0% -79.53% (p=0.000 n=5+4) TrimSpace/ASCII-8 33.5ns ± 2% 6.0ns ± 3% -82.05% (p=0.008 n=5+5) TrimSpace/SomeNonASCII-8 97.1ns ± 1% 88.6ns ± 1% -8.68% (p=0.008 n=5+5) TrimSpace/JustNonASCII-8 144ns ± 0% 143ns ± 0% ~ (p=0.079 n=4+5) bytes.TrimSpace: name old time/op new time/op delta TrimSpace/NoTrim-8 18.9ns ± 1% 4.1ns ± 1% -78.34% (p=0.008 n=5+5) TrimSpace/ASCII-8 29.9ns ± 0% 6.3ns ± 1% -79.06% (p=0.008 n=5+5) TrimSpace/SomeNonASCII-8 91.5ns ± 0% 82.3ns ± 0% -10.03% (p=0.008 n=5+5) TrimSpace/JustNonASCII-8 150ns ± 0% 150ns ± 0% ~ (all equal) Fixes #29122 Change-Id: Ica45cd86a219cadf60173ec9db260133cd1d7951 Reviewed-on: https://go-review.googlesource.com/c/go/+/152917 Reviewed-by: Daniel Martí Reviewed-by: Brad Fitzpatrick Run-TryBot: Daniel Martí TryBot-Result: Gobot Gobot --- src/bytes/bytes_test.go | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) (limited to 'src/bytes/bytes_test.go') diff --git a/src/bytes/bytes_test.go b/src/bytes/bytes_test.go index 80a54f6118..98ba95009d 100644 --- a/src/bytes/bytes_test.go +++ b/src/bytes/bytes_test.go @@ -1617,9 +1617,21 @@ func BenchmarkFieldsFunc(b *testing.B) { } func BenchmarkTrimSpace(b *testing.B) { - s := []byte(" Some text. \n") - for i := 0; i < b.N; i++ { - TrimSpace(s) + tests := []struct { + name string + input []byte + }{ + {"NoTrim", []byte("typical")}, + {"ASCII", []byte(" foo bar ")}, + {"SomeNonASCII", []byte(" \u2000\t\r\n x\t\t\r\r\ny\n \u3000 ")}, + {"JustNonASCII", []byte("\u2000\u2000\u2000☺☺☺☺\u3000\u3000\u3000")}, + } + for _, test := range tests { + b.Run(test.name, func(b *testing.B) { + for i := 0; i < b.N; i++ { + TrimSpace(test.input) + } + }) } } -- cgit v1.3