blob: 946786aa1695d46a3716de2314a0b1d7f6d58173 [file] [log] [blame]
// Copyright 2023 The Wuffs Authors.
//
// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
// https://www.apache.org/licenses/LICENSE-2.0> or the MIT license
// <LICENSE-MIT or https://opensource.org/licenses/MIT>, at your
// option. This file may not be copied, modified, or distributed
// except according to those terms.
//go:build ignore
// +build ignore
package main
// This program exercises the Go standard library's JPEG decoder.
//
// Wuffs' C code doesn't depend on Go per se, but this program gives some
// performance data for specific Go JPEG implementations. The equivalent Wuffs
// benchmarks (on the same test images) are run via:
//
// wuffs bench std/jpeg
import (
"bytes"
"fmt"
"image"
"image/draw"
"image/jpeg"
"os"
"runtime"
"time"
)
const (
iterscale = 20
reps = 5
)
type testCase = struct {
benchname string
src []byte
itersUnscaled uint32
}
var testCases = []testCase{{
benchname: "go_jpeg_decode_19k_8bpp",
src: mustLoad("test/data/bricks-gray.jpeg"),
itersUnscaled: 100,
}, {
benchname: "go_jpeg_decode_30k_24bpp_progressive",
src: mustLoad("test/data/peacock.progressive.jpeg"),
itersUnscaled: 50,
}, {
benchname: "go_jpeg_decode_30k_24bpp_sequential",
src: mustLoad("test/data/peacock.default.jpeg"),
itersUnscaled: 50,
}, {
benchname: "go_jpeg_decode_77k_24bpp",
src: mustLoad("test/data/bricks-color.jpeg"),
itersUnscaled: 30,
}, {
benchname: "go_jpeg_decode_552k_24bpp_420",
src: mustLoad("test/data/hibiscus.regular.jpeg"),
itersUnscaled: 5,
}, {
benchname: "go_jpeg_decode_552k_24bpp_444",
src: mustLoad("test/data/hibiscus.primitive.jpeg"),
itersUnscaled: 5,
}, {
benchname: "go_jpeg_decode_4002k_24bpp",
src: mustLoad("test/data/harvesters.jpeg"),
itersUnscaled: 1,
}}
func mustLoad(filename string) []byte {
src, err := os.ReadFile("../../" + filename)
if err != nil {
panic(err.Error())
}
return src
}
func main() {
if err := main1(); err != nil {
os.Stderr.WriteString(err.Error() + "\n")
os.Exit(1)
}
}
func main1() error {
fmt.Printf("# Go %s\n", runtime.Version())
fmt.Printf("#\n")
fmt.Printf("# The output format, including the \"Benchmark\" prefixes, is compatible with the\n")
fmt.Printf("# https://godoc.org/golang.org/x/perf/cmd/benchstat tool. To install it, first\n")
fmt.Printf("# install Go, then run \"go install golang.org/x/perf/cmd/benchstat\".\n")
for i := -1; i < reps; i++ {
for _, tc := range testCases {
runtime.GC()
start := time.Now()
iters := uint64(tc.itersUnscaled) * iterscale
numBytes, err := decode(tc.src)
if err != nil {
return err
}
for j := uint64(1); j < iters; j++ {
decode(tc.src)
}
elapsedNanos := time.Since(start)
kbPerS := numBytes * uint64(iters) * 1000000 / uint64(elapsedNanos)
if i < 0 {
continue // Warm up rep.
}
fmt.Printf("Benchmark%-30s %8d %12d ns/op %8d.%03d MB/s\n",
tc.benchname, iters, uint64(elapsedNanos)/iters, kbPerS/1000, kbPerS%1000)
}
}
return nil
}
func decode(src []byte) (numBytes uint64, retErr error) {
m, err := jpeg.Decode(bytes.NewReader(src))
if err != nil {
return 0, err
}
b := m.Bounds()
n := uint64(b.Dx()) * uint64(b.Dy())
// Convert YCbCr to RGBA.
if _, ok := m.(*image.YCbCr); ok {
dst := image.NewRGBA(b)
draw.Draw(dst, b, m, b.Min, draw.Src)
m = dst
}
pix := []byte(nil)
switch m := m.(type) {
case *image.Gray:
n *= 1
case *image.RGBA:
n *= 4
pix = m.Pix
default:
return 0, fmt.Errorf("unexpected image type %T", m)
}
// Convert RGBA => BGRA.
if pix != nil {
for i, iEnd := 0, len(pix)/4; i < iEnd; i += 4 {
pix[(4*i)+0], pix[(4*i)+2] = pix[(4*i)+2], pix[(4*i)+0]
}
}
return n, nil
}