C# 线程安全的集合
参考网址: https://docs.microsoft.com/en-us/dotnet/standard/collections/thread-safe/
Thread-Safe Collections
The .NET Framework 4 introduces the System.Collections.Concurrent namespace, which includes several collection classes that are both thread-safe and scalable. Multiple threads can safely and efficiently add or remove items from these collections, without requiring additional synchronization in user code. When you write new code, use the concurrent collection classes whenever multiple threads will write to the collection concurrently. If you are only reading from a shared collection, then you can use the classes in the System.Collections.Generic namespace. We recommend that you do not use 1.0 collection classes unless you are required to target the .NET Framework 1.1 or earlier runtime.
Thread Synchronization in the .NET Framework 1.0 and 2.0 Collections
The collections introduced in the .NET Framework 1.0 are found in the System.Collections namespace. These collections, which include the commonly used ArrayList and Hashtable, provide some thread-safety through the Synchronized
property, which returns a thread-safe wrapper around the collection. The wrapper works by locking the entire collection on every add or remove operation. Therefore, each thread that is attempting to access the collection must wait for its turn to take the one lock. This is not scalable and can cause significant performance degradation for large collections. Also, the design is not completely protected from race conditions. For more information, see Synchronization in Generic Collections.
The collection classes introduced in the .NET Framework 2.0 are found in the System.Collections.Generic namespace. These include List<T>, Dictionary<TKey,TValue>, and so on. These classes provide improved type safety and performance compared to the .NET Framework 1.0 classes. However, the .NET Framework 2.0 collection classes do not provide any thread synchronization; user code must provide all synchronization when items are added or removed on multiple threads concurrently.
We recommend the concurrent collections classes in the .NET Framework 4 because they provide not only the type safety of the .NET Framework 2.0 collection classes, but also more efficient and more complete thread safety than the .NET Framework 1.0 collections provide.
Fine-Grained Locking and Lock-Free Mechanisms
Some of the concurrent collection types use lightweight synchronization mechanisms such as SpinLock, SpinWait, SemaphoreSlim, and CountdownEvent, which are new in the .NET Framework 4. These synchronization types typically use busy spinning for brief periods before they put the thread into a true Wait state. When wait times are expected to be very short, spinning is far less computationally expensive than waiting, which involves an expensive kernel transition. For collection classes that use spinning, this efficiency means that multiple threads can add and remove items at a very high rate. For more information about spinning vs. blocking, see SpinLock and SpinWait.
The ConcurrentQueue<T> and ConcurrentStack<T> classes do not use locks at all. Instead, they rely on Interlocked operations to achieve thread-safety.
Note
Because the concurrent collections classes support ICollection, they provide implementations for the IsSynchronized and SyncRoot properties, even though these properties are irrelevant. IsSynchronized
always returns false
and SyncRoot
is always null
(Nothing
in Visual Basic).
The following table lists the collection types in the System.Collections.Concurrent namespace.
Type | Description |
---|---|
BlockingCollection<T> | Provides bounding and blocking functionality for any type that implements IProducerConsumerCollection<T>. For more information, see BlockingCollection Overview. |
ConcurrentDictionary<TKey,TValue> | Thread-safe implementation of a dictionary of key-value pairs. |
ConcurrentQueue<T> | Thread-safe implementation of a FIFO (first-in, first-out) queue. |
ConcurrentStack<T> | Thread-safe implementation of a LIFO (last-in, first-out) stack. |
ConcurrentBag<T> | Thread-safe implementation of an unordered collection of elements. |
IProducerConsumerCollection<T> | The interface that a type must implement to be used in a BlockingCollection . |
Related Topics
Title | Description |
---|---|
BlockingCollection Overview | Describes the functionality provided by the BlockingCollection<T> type. |
How to: Add and Remove Items from a ConcurrentDictionary | Describes how to add and remove elements from a ConcurrentDictionary<TKey,TValue> |
How to: Add and Take Items Individually from a BlockingCollection | Describes how to add and retrieve items from a blocking collection without using the read-only enumerator. |
How to: Add Bounding and Blocking Functionality to a Collection | Describes how to use any collection class as the underlying storage mechanism for an IProducerConsumerCollection<T> collection. |
How to: Use ForEach to Remove Items in a BlockingCollection | Describes how to use foreach , (For Each in Visual Basic) to remove all items in a blocking collection. |
How to: Use Arrays of Blocking Collections in a Pipeline | Describes how to use multiple blocking collections at the same time to implement a pipeline. |
How to: Create an Object Pool by Using a ConcurrentBag | Shows how to use a concurrent bag to improve performance in scenarios where you can reuse objects instead of continually creating new ones. |
Reference
Recommended content
ConcurrentQueue<T> Class (System.Collections.Concurrent)
Represents a thread-safe first in-first out (FIFO) collection.
ConcurrentBag<T> Class (System.Collections.Concurrent)
Represents a thread-safe, unordered collection of objects.
When to Use a Thread-Safe Collection
Know when to use a thread-safe collection in .NET. There are 5 collection types that are specially designed to support multithreaded add & remove operations.
C# 线程安全的集合的更多相关文章
- java 中如何声明线程安全的集合 set, map 和list
线程安全的集合 http://blog.sina.com.cn/s/blog_508938e10102v1ig.html //make thread-safe list List MyStrList ...
- java利用线程池处理集合
java利用线程池处理集合 2018年07月23日 17:21:19 衍夏成歌 阅读数:866 版权声明:本文为博主原创文章,未经博主允许不得转载. https://blog.csdn.net/s ...
- .NET 同步与异步 之 线程安全的集合 (十一)
本随笔续接:.NET 同步与异步 之 警惕闭包(十) 无论之前说的锁.原子操作 还是 警惕闭包,都是为安全保驾护航,本篇随笔继续安全方面的主题:线程安全的集合. 先看一下命名空间:System.Col ...
- java 中如何声明线程安全的集合 set, map 和list【转】
线程安全的集合 引用自 http://blog.sina.com.cn/s/blog_508938e10102v1ig.html //make thread-safe list List MyStrL ...
- Java中线程安全的集合
如果多线程并发的访问与一个数据结构,那么很容易破坏一个数据结构. 例如,一个线程可能要向一个散列表中插入一条数据的过程中,被剥夺了控制权.如果另外一个线程也开始遍历同一个链表,很可能造成混乱,抛出异常 ...
- Java多线程理解:线程安全的集合对象
1.概念介绍 线程安全就是多线程访问时,采用了加锁机制,当一个线程访问该类的某个数据时,进行保护,其他线程不能进行访问直到该线程读取完,其他线程才可使用.不会出现数据不一致或者数据污染. 线程不安全就 ...
- java 多线程 线程安全及非线程安全的集合对象
一.概念: 线程安全:就是当多线程访问时,采用了加锁的机制:即当一个线程访问该类的某个数据时,会对这个数据进行保护,其他线程不能对其访问,直到该线程读取完之后,其他线程才可以使用.防止出现数据不一致或 ...
- CopyOnWriteArrayList线程安全的集合
CopyOnWriteArrayList是线程安全的集合.本身就是安全的,同时只能被一个进程所访问. 属于JUC并发编程里面的内容. public static void main(String[] ...
- Java——线程安全的集合
线程安全的集合 java.util.concurrent包:ConcurrentHashMap,ConcurrentSkipListMap,ConcurrentSkipListSet,Concu ...
- scala 数据结构(十一):流 Stream、视图 View、线程安全的集合、并行集合
1 流 Stream stream是一个集合.这个集合,可以用于存放无穷多个元素,但是这无穷个元素并不会一次性生产出来,而是需要用到多大的区间,就会动态的生产,末尾元素遵循lazy规则(即:要使用结果 ...
随机推荐
- IBM刀箱服务器的SW
刀箱交换机说明: 1.刀箱交换机可以看到的24个口都是ext端口,其中因为授权原因,只激活了前10个端口. 2.交换机配置中的inta端口为服务器直接连接的端口,inta1-inta14,这些都是对应 ...
- FA转发地址
1.FA地址诞生背景和作用 FA 是Forwarding Address的简写.FA是ASBR通告的TYPE 5 LSA中的字段,它的作用是告诉OSPF域内的路由器如何能够更快捷地到达LSA 5所通告 ...
- 『与善仁』Appium基础 — 1、Android系统的测试环境搭建
目录 1.Android操作系统简介 (1)Android系统诞生 (2)Android系统的结构 (3)Android测试环境搭建整体思路 2.Java环境安装 (1)JDK8下载 (2)安装JDK ...
- Spring Boot(三):Spring Boot中的事件的使用 与Spring Boot启动流程(Event 事件 和 Listeners监听器)
前言:在讲述内容之前 希望大家对设计模式有所了解 即使你学会了本片的内容 也不知道什么时候去使用 或者为什么要这样去用 观察者模式: 观察者模式是一种对象行为模式.它定义对象间的一种一对多的依赖关系, ...
- C语言:渔夫打鱼晒网问题
//如果一个渔夫从 2011 年 1 月 1 日开始三天打渔,两天晒网,编程实现当输入 2011 1 月 1 日以后的任意一天,输出该渔夫是在打渔还是在晒网. #include <stdio.h ...
- EasyUI学后总结第一集
1,创建Easyui组件-使用html还是使用js方式? 如果在创建Easyui组件的时候,组件再被更改,那么属于静态组件,对于静态组件不要使用js方式创建--会增加js代码量. 如果创建的Easyu ...
- Unittest方法 -- 测试报告&加载测试类(discover)
import unittestimport HTMLTestRunnerimport osclass F11(unittest.TestCase): def test_001(self): self. ...
- javascript学习(五)之标准对象
一.RegExp:正则表达式是一种用来匹配字符串的强有力的武器.它的设计思想是用一种描述性的语言来给字符串定义一个规则, 凡是符合规则的字符串,我们就认为它"匹配"了,否则,该字符 ...
- root密码找回
1,启动系统时,按上下键,选择第一项,按e. 2,编辑kernel中,将rhgb quiet 替换作init=/bin/sh.回车确认修改 3,根据提示按b键继续启动. 4,进入bash窗口并有管理员 ...
- DC-6 靶机渗透测试
DC-6 渗透测试 冲冲冲,好好学习 . 收获总结写在文末. 操作机:kali 172.66.66.129 靶机:DC-4 172.66.66.136 网络模式:NAT 上来一波 netdiscove ...