.
Pthread_mutex_recursive_np: Nested lock, which allows the same thread to successfully obtain the same lock multiple times and unlock the lock multiple times. For different thread requests, re-compete when the lock thread is unlocked.
Pthread_mutex_errorcheck_np: Check the error lock. If the same thread requests the same lock, edeadlk is returned. Otherwise, the action is the same as that of the pthread_mutex_timed_np type. This ensures that no dea
-8 3000000 411 NS/OP
Finally, let's look at several reader and multiple writer scenarios. It is also possible to see the ring buffer better at multiple cores from the following comparison .
Benchmarkchannelcontention 10000 160892 Ns/opBenchmarkringbuffercontention 2 806834344 ns/opBenchmarkChannelContention-8 314428 Ns/opBenchmarkRingBufferContention-8 10000 182557 Ns/op
ring buffer uses only CAS operations to achieve thread safety. We can see that the decision to select channel
In the previous section, we introduced how to use lock to synchronize threads. In fact, this lock is a barrier of C #. When the C # compiler compiles the lock statement, it is compiled into the Monitor class. Let's take a look at the following C # source code:
Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/-->Public static void MyLock ()
{
Lock (typeof (Program ))
{
}
}
The above Code uses the lock statement to synchronize MyLock. After this metho
in the previous session, we introduced the use of lock to achieve synchronization between threads. In fact, this lock is a fake in C #, compiled into a call to the Monitor class when the C # compiler compiles the lock statement . Let's look at the following C # source code:
Code highlighting produced by Actipro CodeHighlighter (freeware)http://www.CodeHighlighter.com/--> PublicStaticvoidMyLock (){Lock(typeof(program)){}}The above code synchronizes the MyLock with the lock statement , which is c
Re-lock when not unlocked
Unlock when not in use
Unlock when unlocked
Pthread_mutex_normal (General)
Dead lock
Not defined
Not defined
Pthread_mutex_errorcheck (Error checking)
return error
return error
return error
Pthread_mutex_recursive (Recursive)
Allow
return error
return error
Pthre
usually default null
Before you initialize a mutex, you must clear the memory in which it resides.
If the mutex is initialized, it is in an unlocked state. Mutexes can be in memory shared between processes or in the private memory of a process.
2 Lock Mutual-exclusion lock
Function Prototypes:
int Pthread_mutex_lock (pthread_mutex_t *mutex); #include
Function Description:
When Pthread_mutex_lock () is returned, the mutex is locked. The calling thre
ensure maximum concurrency. SQLite uses the lock step-up mechanism, in order to write the database, the connection needs to obtain an exclusive lock. SQLite has 5 different lock states: unlocked (unlocked), share (shared), reserved (RESERVED), Pending (PENDING), and Exclusive (EXCLUSIVE). Each database connection can only be in one state at a time. Each state (with the exception of an
the page cache and reduce the memory usage of the server.Extension the life cycle of API transaction transactions
What exactly is running under the transaction.For each database object in each data connection, there is a b-tree and pager object. Pager manages transactions, locks, caches, crash recovery.
When the transaction starts, when it ends, and when it begins to affect other database connections.It can be as short as a statement and can grow until you command the end. An opera
The mutex has a reentrant, non-reentrant score. In the C + + standard library, a mutex is used to represent a non-reentrant mutex, and a recursive_mutex is used to represent a reentrant mutex. For these two classes to increase the ability to block threads based on time, there are two new mutex locks: timed_mutex (non-reentrant locks), Recursive_timed_mutex (reentrant locks).All mutexes of the C + + standard library are non-copy and cannot be moved.Mutex basic operationsLock Lock If the mutex is
unlocked when the lock line is being added.
PTHREAD_MUTEX_ERRORCHECK_NP, check the wrong lock, if the same thread request the same lock, then return EDEADLK, otherwise the same as the PTHREAD_MUTEX_TIMED_NP type action. This ensures that the simplest case deadlock does not occur when multiple locks are not allowed.
PTHREAD_MUTEX_ADAPTIVE_NP, adapt to the lock, the simplest type of lock, only wait to unlock after the competition.
3. Lock operation
L
discarded, then backtracking back to a non-canceled forward node, the infinite loop of the return false,acquirequeued method calls the method recursively until rule 1 returns true. Cause thread Blocking
Rule 3: If the former node state is a signal, cancelled, then the state of the previous relay is signal, returning false to the acquirequeued infinite loop, with rule 2
Generally speaking, Shouldparkafterfailedacquire is to rely on the front of the node to determine whether the current thread sh
Sprint (S edition)
The S-Version full price machine (bare metal) purchased at Apple's official retail store is unlocked.
The full price machine purchased at the sprint business Radioshacktargetwalmartbestbuy still belongs to a lock machine.
Domestic users note: The sprint version uses the UICC SIM card of a special sprint operator, unlike other operators ' SIM cards!
Mobile phones and UICC SIM cards are always detected and paired, only Sprint's SI
unlocked by the exclusive lockL pthread_mutex_trylock and Pthread_mutex_lock are similar, but it always returns immediately, regardless of whether the mutex being manipulated is locked, is a non-blocking version of Pthread_mutex_lock. Pthread_mutex_trylock the lock operation when the target mutex is not locking, otherwise the EBUSY error code will be returned. Note: The Pthread_mutex_lock and Pthread_mutex_trylock discussed here are for normal locks,
intentFilter when the screen is unlocked. addAction (Intent. ACTION_USER_PRESENT); // The context is triggered when the user wakes up the handheld device again. registerReceiver (screenBroadcastReceiver, intentFilter); Log. I ("screenBR", "screenBroadcastReceiver registered");} // rewrite broadcast class extends BroadcastReceiver {@ Overridepublic void onReceive (Context context, Intent intent) {String strAction = intent. getAction (); if (Intent. AC
relationship called a chain. A chain relationship exists whenever an object can send a message to another object. It is the message itself that passes on the chain. They are represented as smaller arrows. Messages are marked with the message name, message sequence number, and any guardianship conditions used.The sequential number with dots represents the hierarchy of calls. The Treemap.add function (message 1) calls the Treemapnode.add function (message 1.1). Therefore, message 1.1 is the first
This article is mainly to share with you the PHP file lock concurrency operation, the default: PHP file operation function, not blocking state, but free operation State, hope to help everyone.
Conditions:
A file lock is required when a script operation is required to block additional script operations.
Lock Operation Flow:
Lock first, detect if the lock is successful, if you use it successfully!
Lock type:
Read Lock: S-lock (share-lock) shared lock, expected to increas
Receipt Validation ProgrammingGuide.) The user has access to all content published between each start and end date, as well as the content is initially UN Locked when the subscription was purchased. If the subscription lapsed, there'll be is multiple periods of time during which the subscription was active, and there wil L be pieces of content unlocked at the beginning of a subscription period.To implement this logic in your application, keep a date
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