LockLocks and semaphores are very familiar to most people, especially common mutexes. There are many kinds of locks, mutual exclusion locks, spin locks, read and write locks, sequential locks, and so on, here are just a few things to see, Mutual exclusion LockThis is the most common, Win32:createmutex-waitforsingleobject-releasemutex,linux pthread_mutex_lock-pthread_mutex_unlock,c. #的lock和Monitor, Java Lock
Preface
In fact, the title is more appropriate to use a mutex mechanism, the main two problems in concurrency is: how the thread synchronization and how the thread communicates.
Synchronization is mainly through mutual exclusion mechanism to ensure that the mutual exclusion mechanism we are most familiar with the lock, of course, there is no lock of CAS implementation.
Multi-threaded shared resources, suc
Basic ConceptsIn this chapter, we will explain the principle of "thread access to Fair lock", and we need to understand a few basic concepts before explaining it. The following are all based on these concepts, which may be tedious, but from these concepts, you can see some of the architecture of the Java lock, which is helpful for us to know about locks.1. AQS -refers to the Abstractqueuedsynchronizer class
Go to: http://blog.sina.com.cn/s/blog_6d7fa49b01014q7p.htmlMany people ask this question, what does the Linux kernel do to provide a variety of synchronization lock mechanisms? Traced is actually due to the existence of multiple processes in the operating system concurrent access to shared resources, resulting in the race between processes. These include the SMP system we know, the competing resources between multiple cores, the competition between si
The most common way:
int a =;
Note: In general, this will be set to a class variable, such as the Zhi in Segement and the global lock in copyonwritearraylist
final reentrantlock lock = new Reentrantlock () ;
Lock.lock ()//Get lock
try {
a++;//business logic
} catch (Exception e) {
}final
Reprint: http://weibo.com/p/1001603906313603156948 Yellow highlight is the error warning, the severity of error is high, 1 respectively Assets/standard assets/scripts/ MeshCombineUtility.cs (27,74): Error cs1061:type ' Unityengine.mesh ' does not contain a definition for ' gettrianglestrip ' a nd no extension method ' Gettrianglestrip ' of type ' Unityengine.mesh ' could is found (are you missing a using directive or An assembly reference?)
2) Assets/standard Assets/scripts/meshcombineutility.
public void Bossrotaition ()
{
quaterion loktion=quaterion.lookrotation ( player.instrance.transform.position-transform.position);
Transform.localrotion=quaterion.lerp (transform.rotation,looktion,0.2f);
}
(Simple four-element rotation)* I wrote a boss rotation attack player method, with four elements, Quaterion.lookrotation () method to fill in a direction (player coordinates-boss coordinates to get boss to the player direction);And then assign a value to the loclrotion, to look like a spin
Locking mechanism used in multiple CPU systems, when a CPU is accessing the critical section of the spin lock protection, the critical section will be locked, the other need to access the critical section of the CPU can only busy wait until the previous CPU has access to the critical section, the critical section unlocked. The spin lock allows the waiting thread to wait for the busy waits instead of sleep b
The last tool in the lock is introduced from this section: read-write Lock (Readwritelock).Reentrantlock implements a standard mutex, which is the notion that only one thread can hold a lock at a time, or the so-called exclusive lock. This feature has been emphasized in the previous chapters. Obviously this feature red
MySQL lock usage-row-Level Lock is the smallest lock in MySQL, which can greatly reduce database operation conflicts. However, the smaller the granularity, the higher the implementation cost. The MYISAM engine only supports table-level locks, while the INNODB Engine supports row-level locks. The following content is also for INNODB row-level locks. Row-level lock
LS) {Console.WriteLine (item * item); LS. Remove (item); }Generates a run-time error in LS. Remove (item) This line because foreach is read-only. Cannot be modified while traversing.59: Does Unity3d support writing multithreaded programs? What do you need to pay attention to if supported?Only components that can access Unity3d from the main thread, objects and Unity3d system callsSupport: If you have to deal with a lot of things at the same time or interact with
Row-level locks are the smallest type of locks in MySQL, which can greatly reduce database operation conflicts. However, the smaller the granularity, the higher the implementation cost. The MYISAM engine only supports table-level locks, while
Row-level locks are the smallest type of locks in MySQL, which can greatly reduce database operation conflicts. However, the smaller the granularity, the higher the implementation cost. The MYISAM engine only supports table-level locks, while
Row-level l
Previous continuedA murder caused by a lock-free message queue: How to be a real programmer? (a)--ground: CauseA murder caused by a lock-free message queue: How to be a real programmer? (b)--month: Spin lockParallel spaceIn the copy of the above line I stopped first, is considered to occupy a position, although I know how to write, but the feeling is still very messy.I suddenly thought, since so tangled, so
Prior to Java5.0, only synchronized (built-in lock) and volatile. The display lock Reentrantlock is introduced after Java5.0.
Reentrantlock OverviewThe Reentrantlock is a reentrant lock, which differs from the built-in lock, which needs to display the lock and unlock fo
Before Java5.0, only synchronized (built-in locks) and volatile. The display lock Reentrantlock is introduced after Java5.0.
Reentrantlock Overview
Reentrantlock is a reentrant lock, unlike a built-in lock, which needs to be displayed for lock and unlock every time it is used, and provides more advanced features: Fai
Oracle lock 1: DML lockDML lock, also known as data lock, is used to ensure data integrity when multiple users operate on data. DML lock prevents conflicting DML and DDL operations at the same time.
DML Locks include Row Locks (TX) and Table Locks (TM). Different DML operations will automatically request the correspond
This article from: http://blog.163.com/hbu_lijian/blog/static/126129153201261722410353/
Kernel synchronization measures (for Linux kernel)
To avoid concurrency and prevent competition. The kernel provides a set of Synchronization Methods to protect shared data. Our focus is not to introduce the detailed usage of these methods, but to emphasize the difference between these methods and them.The synchronization mechanism used in Linux has been continuously improved since 2.0 to 2.6. From the initia
A bloodcase caused by a lock-free Message Queue: how to be a real programmer? (2) -- month: spin lock, queue spinPrefix
A bloodcase caused by a lock-free Message Queue: how to be a real programmer? (1) -- location: Cause
A bloodcase caused by a lock-free Message Queue: how to be a real programmer? (2) -- month: spin lo
One: OverviewCompared with other databases, MySQL's locking mechanism is relatively simple, and its most notable feature is that different storage engines support different locking mechanisms. For example, the MyISAM and memory storage engines use table-level locks (table-level locking), InnoDB storage engines support row-level locks (row-level locking) and table-level locks, but row-level locks are used by default.MySQL main two types of lock charact
Pessimistic lock Introduction (encyclopedia):
A pessimistic lock, as its name implies, is conservative in that the data is modified by the outside world (including other transactions of the system, as well as transactions from the external system), so that the data is locked during the entire process of processing. Pessimistic lock implementation, often rely on t
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