Golang初學者對函數傳回值還是指標的測試

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

先把簡單的代碼貼出來，然後再廢話。

先是benchmark的命令

go test -bench=Poin -memprofile=pointermem.pprof -memprofilerate=1 -benchmem

go test -bench=Value -memprofile=valuemem.pprof -memprofilerate=1 -benchmem

然後是pprof的結果，先是pointer的，再是value的，可以看到pointer的報告2allocs/op

package maintype mytype struct {field1 stringfield2 stringfield3 stringfield4 stringfield5 stringfield6 stringfield7 stringfield8 stringfield9 string}func returnValue() mytype {return mytype{field1: "abc",field2: "aaa",field3: "vvv",field4: "ddd",field5: "394834",field6: "sdfbd34534",field7: "asdf34534d90sdfsd",field8: "asdf3424jjiiihiu",field9: "vmxvbxcvb8rewasdfasdf",}}func returnPointer() *mytype {return &mytype{field1: "abc",field2: "aaa",field3: "vvv",field4: "ddd",field5: "394834",field6: "sdfbd34534",field7: "asdf34534d90sdfsd",field8: "asdf3424jjiiihiu",field9: "vmxvbxcvb8rewasdfasdf",}}func main() {}

package mainimport ("fmt""testing")func BenchmarkReturnValue(b *testing.B) {var x mytypefor i := 0; i < b.N; i++ {x = returnValue()fmt.Println(x)}}func BenchmarkReturnPointer(b *testing.B) {var x *mytypefor i := 0; i < b.N; i++ {x = returnPointer()fmt.Println(*x)}}