Commit 41d0dc49 authored by Robert Griesemer's avatar Robert Griesemer

go/format: add simple benchmark framework and basic benchmark

For now, this CL adds as a first benchmark the formatting of
a 10,000 element array literal. It is easy to add additional
test cases as we see fit.

	name                   time/op
	Format/array1-10000-4    26.7ms ± 7%

	name                   speed
	Format/array1-10000-4  2.43MB/s ± 6%

	name                   alloc/op
	Format/array1-10000-4    5.52MB ± 0%

	name                   allocs/op
	Format/array1-10000-4      119k ± 0%

Updates #26528.

Change-Id: Ic8ec8f70160d122b877740412d4d4406f5f4b345
Reviewed-on: https://go-review.googlesource.com/c/153642Reviewed-by: 's avatarIan Lance Taylor <iant@golang.org>
parent ef780fbf
// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// This file provides a simple framework to add benchmarks
// based on generated input (source) files.
package format_test
import (
"bytes"
"flag"
"fmt"
"go/format"
"io/ioutil"
"testing"
)
var debug = flag.Bool("debug", false, "write .src files containing formatting input; for debugging")
// array1 generates an array literal with n elements of the form:
//
// var _ = [...]byte{
// // 0
// 0x00, 0x01, 0x02, 0x03, 0x04, 0x05, 0x06, 0x07,
// 0x08, 0x09, 0x0a, 0x0b, 0x0c, 0x0d, 0x0e, 0x0f,
// 0x10, 0x11, 0x12, 0x13, 0x14, 0x15, 0x16, 0x17,
// 0x18, 0x19, 0x1a, 0x1b, 0x1c, 0x1d, 0x1e, 0x1f,
// 0x20, 0x21, 0x22, 0x23, 0x24, 0x25, 0x26, 0x27,
// // 40
// 0x28, 0x29, 0x2a, 0x2b, 0x2c, 0x2d, 0x2e, 0x2f,
// 0x30, 0x31, 0x32, 0x33, 0x34, 0x35, 0x36, 0x37,
// ...
//
func array1(buf *bytes.Buffer, n int) {
buf.WriteString("var _ = [...]byte{\n")
for i := 0; i < n; {
if i%10 == 0 {
fmt.Fprintf(buf, "\t// %d\n", i)
}
buf.WriteByte('\t')
for j := 0; j < 8; j++ {
fmt.Fprintf(buf, "0x%02x, ", byte(i))
i++
}
buf.WriteString("\n")
}
buf.WriteString("}\n")
}
var tests = []struct {
name string
gen func(*bytes.Buffer, int)
n int
}{
{"array1", array1, 10000},
// add new test cases here as needed
}
func BenchmarkFormat(b *testing.B) {
var src bytes.Buffer
for _, t := range tests {
src.Reset()
src.WriteString("package p\n")
t.gen(&src, t.n)
data := src.Bytes()
if *debug {
filename := t.name + ".src"
err := ioutil.WriteFile(filename, data, 0660)
if err != nil {
b.Fatalf("couldn't write %s: %v", filename, err)
}
}
b.Run(fmt.Sprintf("%s-%d", t.name, t.n), func(b *testing.B) {
b.SetBytes(int64(len(data)))
b.ReportAllocs()
b.ResetTimer()
for i := 0; i < b.N; i++ {
var err error
sink, err = format.Source(data)
if err != nil {
b.Fatal(err)
}
}
})
}
}
var sink []byte
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