/
main.go
76 lines (64 loc) · 1.15 KB
/
main.go
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package main
import (
"fmt"
"io/ioutil"
"os"
"runtime"
"runtime/pprof"
)
func main() {
memFile, err := os.Create("mem.pprof")
if err != nil {
panic(err)
}
defer memFile.Close()
badPart()
goodPart()
if err = pprof.WriteHeapProfile(memFile); err != nil {
panic(err)
}
}
func badPart() {
badData := getBadData()
println("getBadData:", *badData, len(*badData))
gc()
}
func goodPart() {
var goodData []byte
getGoodData(&goodData)
println("getGoodData", goodData, len(goodData))
gc()
}
//go:noinline
func getBadData() *[]byte {
data := bigData() // :52:2: data escapes to heap
logGC(&data, "badData")
return &data
}
//go:noinline
func getGoodData(data *[]byte) { // :57:18: data does not escape
*data = bigData()
logGC(data, "goodData")
}
func bigData() []byte {
file, err := os.Open("./agile.png")
if err != nil {
panic(err)
}
defer file.Close()
data, err := ioutil.ReadAll(file)
if err != nil {
panic(err)
}
return data
}
func logGC(data *[]byte, name string) {
runtime.SetFinalizer(data, func(interface{}) {
fmt.Printf("%s garbage collected\n", name)
})
}
func gc() {
println("GC...")
runtime.GC()
println("...GC")
}