cas operation

What is atomic manipulationOne or a series of operations that cannot be interruptedWays to implement atomic operationsJava can implement atomic operations by locking and looping CASCAS (Compare and Swap) Why should I have CAS?Compare and swap is an

ABA problems caused by CAS (Compare and Swap)Problem description In multi-threaded situations, each thread uses CAS operations to modify data A to B, but we only want one thread to modify the data correctly and modify it only once. When

Synchronization: Shared resources are called by multiple threads and are synchronized in several ways: (Scenario: Selling train tickets)1 syncnizerd Keywords2 Reentrantlock Row It lock3 volatile keyword modifier variable;Async: Changing the state of

1. PrefaceThe 7th section explains the future in the threading model of Java and explains why the main thread can get the result of the thread pool task and become a synchronous state. The secret is that Java has all the runnable and callable tasks,

Memcache, as an excellent out-of-process cache, is often used in high-concurrency system architectures. Here's a look at how to view memcache health and manage maintenance of its key through the Telnet tool. Suppose memcache installation

40 Questions Summary1. What is the use of multithreading?A question that may seem a little ridiculous to many people: I can use multithreading, and what's the use of it? In my opinion, this answer is even more nonsense. The so-called "know the

1. Longadder and Atomiclong similar use, but the performance is better than Atomiclong. Both Longadder and Atomiclong use atomic operations to improve performance. But longadder on the basis of Atomiclong, hot spot separation is similar to the

Read a bunch of articles, and finally the Java CAS principle in-depth analysis of the clear. Thanks to Google's powerful search, to take this sarcastic Baidu, rely on Baidu to learn nothing. Reference

The Java.util.concurrent package is built entirely on CAS and will not have this package without CAs. The importance of CAs is visible. CAS Cas:compare and swap, translated into comparisons and exchanged. In Java.util.concurrent package, a kind of

In programming, we usually create a thread directly when we need to use a thread, which is convenient to implement, but it also poses the same problem:If a large number of concurrent threads are required, after each thread is created, a task with a

CAS operations can be divided into the following three steps: Step 1. Read the old value (that is, the value of the variable to be read from system memory, for example: reading the value of the variable i) Step 2. Novelty value (that is, the value

Reprint Please indicate the source: http://blog.csdn.net/ns_code/article/details/17487337 Simple use of lock lock The new lock mechanism--java.util.concurrent.locks explicit mutex in Java 5: The Lock interface, which provides a more extensive

In concurrent programming, it is sometimes necessary to use thread-safe queues. There are two ways to implement a thread-safe queue: One is to use a blocking algorithm and the other is to use a non-blocking algorithm. Queues using blocking

I saw the use of lock yesterday when I was learning about the interview experience shared by others. Think of myself in the last interview also encountered the difference between synchronized and lock and use. So I sorted out the difference and use

What scenario requires the use of locks. In a multi-node deployment or multithreaded execution, there may be multiple threads updating the same data at the same time, resulting in a conflict, which is the concurrency problem. In this case, the

Address: http://www.cnblogs.com/chencheng/p/3527692.html implementation of a lock-free queue-loop array Lock-Free design via CAS operation: CAS Atomic operations (Compare & Set): Contains three operands, memory value V, the old expected value

Performance Comparison In JDK1.5, synchronized is inefficient. Because this is a heavyweight operation, its greatest performance impact is the implementation, suspend the thread and recover the thread of the operation need to go into the kernel

A coupon sharing feature was recently made, and one of the features was to generate a coupon sharing short link. The resulting short link requires that each link be unique, and that the length is as short as possible. On the internet to look up the

Optimistic lockAlways think that there is no concurrency problem, every time you go to fetch data, always think that there will be no other threads to modify the data, so it will not be locked, but in the update will be judged that other threads

Introduction In the previous article, the Reentrantlock principle based on Aqs was analyzed in detail, and Reentrantlock represented an exclusive lock through the transformation between the state variables 0 and 1 in Aqs. So can you think about what