[Go 编程语言] go 的内存使用疑问

[小天管理]

下面这段代码：

package main

import (
	"fmt"
	"runtime"
	"unique"
)

func printMemUsage() {
	var m runtime.MemStats
	runtime.ReadMemStats(&m)

	fmt.Printf("Alloc = %v B", m.Alloc)
	fmt.Printf("\tTotalAlloc = %v B", m.TotalAlloc)
	fmt.Printf("\n")
}

type TestStruct struct {
	A float64
	B float64
	C float64
	D float64
}

func main() {
	testobj1 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()

	testobj2 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()

	testobj3 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()

	testobj4 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()
	fmt.Println(testobj1, testobj2, testobj3, testobj4)
	fmt.Println("---------")

	uniqueobj1 := unique.Make(TestStruct{A: 1, B: 2, C: 3, D: 4})
	printMemUsage()

	uniqueobj2 := unique.Make(TestStruct{A: 1, B: 2, C: 3, D: 4})
	printMemUsage()

	uniqueobj3 := unique.Make(TestStruct{A: 1, B: 2, C: 3, D: 4})
	printMemUsage()

	uniqueobj4 := unique.Make(TestStruct{A: 1, B: 2, C: 3, D: 4})
	printMemUsage()
	fmt.Println(uniqueobj1, uniqueobj2, uniqueobj3, uniqueobj4)
	fmt.Println("---------")

	testobj5 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()

	testobj6 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()

	testobj7 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()

	testobj8 := TestStruct{A: 1, B: 2, C: 3, D: 4}
	printMemUsage()
	fmt.Println(&testobj5, &testobj6, &testobj7, &testobj8)

}

输出结果是：

Alloc = 118256 B        TotalAlloc = 118256 B
Alloc = 119704 B        TotalAlloc = 119704 B
Alloc = 119720 B        TotalAlloc = 119720 B
Alloc = 119736 B        TotalAlloc = 119736 B
{1 2 3 4} {1 2 3 4} {1 2 3 4} {1 2 3 4}
---------
Alloc = 121056 B        TotalAlloc = 121056 B
Alloc = 121072 B        TotalAlloc = 121072 B
Alloc = 121088 B        TotalAlloc = 121088 B
Alloc = 121104 B        TotalAlloc = 121104 B
{0x1400001e180} {0x1400001e180} {0x1400001e180} {0x1400001e180}
---------
Alloc = 121152 B        TotalAlloc = 121152 B
Alloc = 121200 B        TotalAlloc = 121200 B
Alloc = 121248 B        TotalAlloc = 121248 B
Alloc = 121296 B        TotalAlloc = 121296 B
&{1 2 3 4} &{1 2 3 4} &{1 2 3 4} &{1 2 3 4}

本来是想试一下 unique 包对于内存的节约效果的，但是没想到第一种写法，每次也只增加了 16B ，和用了 unique 效果一样

而第三种写法，和第一种相比，确实每次用的内存多了，但是为什么后面的 fmt.Println 的写法区别，能影响前面的内存使用量

版本：go 1.23.0

平台：arm macos