xmm-test01.go

/*
   XMM 简单示例 - 01
   XMM Simple Example - 01

   目标：如何在结构体中使用XMM
   Objective: How to use XMM in structures

   说明：示例如何结构体类场景如何使用XMM内存库
   Description: Example of how to use the XMM memory library in a structure class scenario
*/
package main

import (
	"fmt"
	"unsafe"

	"github.com/heiyeluren/xmm"
)

func main() {

	// 定义一个类型(结构体)
	// Define a type (structure)
	type User struct {
		Id     uint
		Name   string
		Age    uint
		Email  string
		Salary float32
	}

	// 初始化XMM对象
	// Initialise the XMM object
	f := &xmm.Factory{}

	// 从操作系统申请一个内存块
	// 如果内存使用达到60%，就进行异步自动扩容，每次异步扩容256MB内存（固定值），0.6这个数值可以自主配置
	// Request a memory block from the operating system
	// If memory usage reaches 60%, asynchronous automatic expansion is performed, each time 256MB of memory is expanded asynchronously (fixed value), the value of 0.6 can be configured independently

	mm, err := f.CreateMemory(0.6)
	if err != nil {
		panic("CreateMemory fail ")
	}

	// 自己从内存块中申请一小段自己想用的内存
	// Request a small section of memory from the memory block yourself that you want to use
	size := unsafe.Sizeof(User{})
	p, err := mm.Alloc(size)
	if err != nil {
		panic("Alloc fail ")
	}

	// 使用该内存块，进行结构体元素赋值
	// Use this memory block for structure element assignment
	user := (*User)(p)
	user.Id = 1
	user.Age = 18
	user.Name = "heiyeluren"
	user.Email = "heiyeluren@example.com"

	// 输出变量，打印整个结构体等
	// Output variables, print entire structures, etc.
	fmt.Println("\n===== XMM X(eXtensible) Memory Manager example 01 ======\n")

	fmt.Println("\n-- Memory data status --\n")
	fmt.Println("User ptr addr: \t", p)
	fmt.Println("User data: \t", user)

	// 释放内存块（实际是做mark标记操作）
	// Free memory blocks (actually doing a mark mark operation)
	mm.Free(uintptr(p))

	// Free()后再看看变量值，只是针对这个内存块进行mark标记动作，并未彻底从内存中释放（XMM设计机制，降低实际gc回收空闲时间）
	// XMM内部会有触发gc的机制，主要是内存容量，参数TotalGCFactor=0.0004，目前如果要配置，需要自己修改这个常量，一般不用管它，Free()操作中有万分之4的概率会命中触发gc~
	// GC触发策略：待释放内存  > 总内存 * 万分之4 会触发gc动作
	// After Free() and then look at the variable value, only for this memory block to mark mark action, not completely released from memory (XMM design mechanism to reduce the actual gc recovery idle time)
	// XMM will have an internal mechanism to trigger gc, mainly memory capacity, parameter TotalGCFactor=0.0004, currently if you want to configure, you need to modify this constant yourself, generally do not bother with it, Free() operation has a 4 in 10,000 probability of hitting the trigger gc ~
	// GC trigger policy: memory to be freed > total memory * 4 in 10,000 will trigger gc action

	fmt.Println("\n-- Memory data status after XMM.Free() --\n")
	fmt.Println("memory ptr addr:\t", p)
	fmt.Println("User data:\t\t", user)

	// 结束
	// End
	fmt.Println("\n===== Example test success ======\n")
}