concurrent programming book

container, but at the time of writing will create a new object to add to the new container, The object of the old container is still in use, so there are two copies of the object memory. If these objects occupy a large amount of memory, say 200M or so, then write 100M data in, memory will occupy 300M, then this time is likely to cause frequent Yong GC and full GC. Before we used a service in our system because the copyonwrite mechanism is used to update large objects every night, resulting in a

Use of Java concurrent programming Thread PoolImplicit coupling between tasks and execution policies The Executor framework can decouple the submission of tasks from the execution policies of tasks (that is, independence ). Although the Executor framework provides considerable flexibility for developing and modifying execution policies, not all tasks can apply all execution policies. For example:Dependency

maximize the use of CPU　　Disadvantages are as follows:1, the nature of the process is single-threaded, unable to use multicore, can be a program to open multiple processes, each process to open multiple threads, each process to open multiple threads, each line range open 2, the association refers to a single thread, so once the association is blocked, it will block the entire thread　　Summary of the characteristics of the process:1. Concurrency must be implemented in only one single thread2. No

Chapter One: Hello the concurrent world of C + +1. What is concurrencyThe simplest and most basic concurrency is the simultaneous movement of two or more independent activities of two or more.For a single processing unit or core, the machine can only perform one task at a time, not enough that it can switch tasks more than once per second. This is called task switching.2. The Concurrency pathway2.1 Multi-processIndependent processes can pass messages

In Java concurrent programming, use ReentrantLock to replace the synchronized keyword primitive.Tags: the Concurrent library package introduced by Java 5 provides ReentrantLock that can be reloaded into the synchronization lock to replace the synchronized keyword primitive, and provides better performance and more powerful functions. The usage is also simple: pub

Apriori condition (precondition): Some methods contain a priori condition based on a state. For example, you cannot remove an element from an empty queue, and the queue must be in a non-empty state before the element is deleted. The operation of a state-based priori condition becomes a dependent state operation. In a single thread, if an operation fails to meet a priori condition, it can only fail, but in a concurrent program a priori condition ma

Use of Java concurrent programming thread pool (3)Thread factory Every time the thread pool needs to create a thread, it is completed through the thread factory method. The default thread factory method creates a new non-daemon thread without special configuration information. By specifying a thread factory method, you can configure the thread pool. Scenarios requiring custom thread factory methods:You need

family members designated a meeting place for the mall: "We meet each other at McDonald's 6:00, and after that, we will decide what to do next."The difference between a level and a latch :Levels: Waiting for other threads, which can be used repeatedly for latching: waiting for an event, can only be used onceWhen a thread reaches the level point, the call is await await blocked until all threads reach the level point. If all threads reach the level point, the level is successfully breac

, the synchronization mechanism adopted a "time-to-space" way: Access serialization, object sharing. The synchronization mechanism is to provide a copy of the variable that all threads can access.2, for the appearance of Atomic, is through the atomic operation instruction +lock-free completes, thus realizes the non-blocking concurrency problem.3, for volatile, for multi-threaded resource sharing problem solved part of the demand, in the case of non-dependent operation, the change of the variable

SubsectionsThread Safety (Threads safety)Locks (Lock)Shared objectsGroup of objectsInfrastructure building BlocksTask executionCancel and closeUse of thread poolsPerformance and ScalabilityTest for concurrent ProgramsShow lockAtomic variables and non-blocking synchronization mechanisms First, thread safety (threads safety)Whenever more than one thread accesses a given state variable. And one of the threads writes the variable, you must use synchroniza

Python's multiprocessing module is used to create multiple processes, and the following summarizes the usage records for multiprocessing.Series Articles Python Concurrent programming Threading thread (i) Multiprocessing process of Python concurrent programming (ii) Asyncio of Python

TCP/IP network programming (transcription note 3) – Zombie process and multitasking concurrent server table of Contents The production of zombie processes Avoid zombie processes Signal Multi-tasking Concurrent server The production of zombie processes Child process exits first, parent process does not exit ==> zombie process

TCP/IP network programming (transcription note 3) – Zombie process and multitasking concurrent server table of Contents The production of zombie processes Avoid zombie processes Signal Multi-tasking Concurrent server The production of zombie processes Child process exits first, parent process does not exit ==> zombie process

, the threads in the queue begin executing. How many threads will be created to perform tasks when the Newfixedthreadpool is changed to Newcachedthreadpool? After changing to Newsinglethreadexecutor, the visible thread makes the task run sequentially, performs one task, and then performs another task. This adds another reason to create a thread pool: Reduce the number of concurrent threads. Creating a large number of threads can greatly degrade perf

First, why need concurrent programmingIn the case of single-threaded programming, if a program encounters a blocking situation, such as an event that waits for I/O to occur, the program can be executed. This will affect the operation of the following programs.Concurrency is the process in which multiple tasks are processed and each task is switched back and forth from the operating system.It feels like many

Java concurrent programming task cancellation (9)Disable Jvm Jvm can be shut down normally or forcibly. There are multiple triggering methods for normal shutdown:When the last normal (non-daemon, what is the daemon thread) thread ends, the system is called. when you exit, or use other platform-specific methods to close the jvm (for example, sending a SIGINT signal or typing Ctrl-c), call the Runtime. halt o

Notes [Java7 Concurrent Programming manual] series catalogueProfileNext, practice modifying the fairness of the lock, and the conditions in which it is used.Modify the fairness of the lock Reentrantlock /** *构造一个锁对象，默认为非公平锁 */ publicReentrantLock(boolean fair) { newnew NonfairSync(); }According to the structure of reentrantlock, it can be seen that the default is to construct a non-f

C + + Concurrent programming wait and wake condition variablescondition variables, including (Std::condition_variable and Std::condition_variable_any)defined in the Condition_variable header file, they all need to work together with the mutex (as a synchronization tool).Std::condition_variable allows blocking of a thread until the condition is reached.member functionsvoid Wait (std::unique_lockWait, by Noti

= ('Alex', Q)) C2=process (target=consumer,args= ('Egon', Q)) " "The daemon ensures that the daemon ends at the end of the master process." "C1.daemon=True C2.daemon=True _p=[P1,P2,P3,C1,C2] forPinch_p:p.start () p1.join () P2.join () P3.join ( )Second, shared memory (Manager)Looking ahead, concurrent programming based on messaging is a trend, and even with threading, the recommended approach is to design a

One gevent moduleGevent is a third-party library that makes it easy to implement concurrent or asynchronous programming through Gevent. The main mode used in Gevent is Greenlet, which is a lightweight process that accesses Python in the form of a C extension module. Greenlet all run inside the main program operating system process, but they are dispatched in a collaborative manner.# usage G1=gevent.spawn (f