experian lock free

Message Queue is the cornerstone of communication on some platforms. The communication between tasks is based on message queues. The processing speed of message queues often affects the performance of the entire system. To avoid multi-task processing of message queues at the same time, A lock is usually required for mutually exclusive access when a task is processing a queue. 1: assume that each module has its own message queue. Any module can send me

Recently, some C #2.0Code... Discover unsafe implementations of various threads No concurrentcollection classes in 2.0 As a last resort, I wrote one myself, Originally intended to use the traditional lock implementation, but considering that the operation is very lightweight... Eventually still uses the lock free Use interlocked to replace common

. CAS is required every time after the change. In high concurrency, the failure probability is very high and it is a vicious circle, the latter has much lower overhead and has no side effects (in the previous issue, the base variable will be counted at sum, and the base value will not be lost ). Therefore, it may be better not to change. 4. Can AtomicLong be discarded?My idea is to discard it, because although LongAdder occupies a little space, its performance is enough to explain everything, wh

Disruptor is an efficient Memory Lock-free queue open-source by Lmax. I have read the relevant design documents and blogs over the past two days. I will try to summarize them below. The first part. IntroductionWhen talking about concurrent program design, there are several concepts that cannot be avoided. 1. locks: locks are the easiest way to implement concurrency. Of course, the price is also the highest.

Precautions for using lock-free queue (ring buffer), queue Loops The circular buffer is a common data structure in the producer and consumer models. The producer puts the data into the end of the array, and the consumer removes the data from the other end of the array. when the end of the array is reached, the producer returns to the header of the array. If there is only one producer and one consumer, the R

CAS atomic Operations--compare Set, or Compare Swap, now almost all CPU instructions support CAS atomic operations, X86 corresponding to CMPXCHG assembly instructions.You should remember the concept of "atomic manipulation" inside the operating system, where an operation is atomic (atomic), and if the upper layer of this operation is not able to find its internal implementation and structure. An atomic operation can be a step or multiple steps, but its order cannot be disrupted, or it can be c

This article provides an implementation code for the C ++ lock-free queue, which is mainly used for one thread to read data and write data in another thread. Copy codeThe Code is as follows: # ifndef LOCK_FREE_QUEUE_H _ # Define LOCK_FREE_QUEUE_H _ // No lock queue, suitable for reading by one thread and writing by one thread# Include Template Class LockFreeQueu

operation.Thread 1 Thread 2MOVL Global,%eax;global value is 5,%eax value of 5Addl $1,%eax;%eax value is 6------Now thread 2 gets execute permission--------->MOVL Global,%eax;global value is 5,%eax value of 5Subl $1,%eax;%eax value is 4MOVL%eax,global;%eax value is 4,global value of 4MOVL%eax,global;%eax value is 4,global value of 4As can be seen from the above example, the result is not that we expect the value of global to remain the original value after 1 minus 1, but from 5 to 4. This is the

1 #ifndef Mutex_class_h2 #defineMutex_class_h3 4 classMutex_class5 {6 Public:7 Mutex_class ();8 void Lock();9 voidunlock ();Ten One Private: A //The following is used, and the general lock is almost - intMutex_value; - }; the - #endif //Mutex_class_h1#include"Mutex_class.h"2#include 3 4 #defineLock_value 05 #defineUnlock_value 16 //nt Mutex_value = lock_value;7 #defineFree_lock (Mutex_val

ringbuf* r = New Ringbuf (); void Svc () {Ullong last = 0;ullong ts = 0;while (1) {Ullong c = (Ullong) r->pop (), if (c = = 0)/** not NULL . */{usleep (+); continue;} if (c-last! = 1) {printf ("It ' s a bug, C:%llu, Last:%llu\n", C, last); exit (1);} Last = c;if ((c% 20000000) = = 0) {Ullong now = Misc::getdida ();/** system ticking. */printf ("TS:%llu, Last:%llu\n", Now-ts, LA ST); ts = Now;}}} int main (int argc, char **argv) {misc::newthread (SVC);/** single thread consumption. *///for (Ullo

(;;) {Increaseheadcount (oldhead); AutoConstNodeptr =oldhead.ptr; if(Nodeptr = =nullptr) { returnShared_ptr(); } if(Head.compare_exchange_strong (Oldhead, nodeptr->Next, std::memory_order_relaxed)) {Std::shared_ptrresult; Result.swap (Nodeptr-data); int ConstIncreasecount = Oldhead.externalcount-2; if(nodeptr->Internalcount.fetch_add (Increasecount, Std::memory_order_release) == -Increasecount) { Deletenodeptr; }

order to make full use of the queue, an end index is added to ensure that at least one data is written to the end of the queue. The variable-length queue data structure is defined as follows:See my blog for details about edge length arrays http://blog.csdn.net/xy010902100449/article/details/46522533 　 typedefstruct{ /*读指针*/ /*写指针*/ /*队列结束指针*/ uint32_t size; /*缓冲区大小*/ char *buff[0]; /*缓冲区起始地址*/}ring_buff_st; Copyright NOTICE: This article for Bo Master original

This is a creation in Article, where the information may have evolved or changed. Lock-free queue for scenarios: Two threads of interaction data, one thread production data, another thread consuming data, high efficiency Cons: Need to use fixed allocated space, can not dynamically increase/decrease length, there is space waste and can not expand the space problem Package Mainimport ( "FMT" "Reflect"

(nodes, last); } voidPushlisttodelchain (node* First, node*Last ) { Last->next =Tobedeletedchainhead; //Put current head of delete chain to the next of the last . //Then let's the first be the head. while(!tobedeletedchainhead.compare_exchange_weak (last->Next, first)); } voidPushnodetodelchain (node*node) {Pushlisttodelchain (node, node); } Public: voidPush (TConstvalue) {AutoConstNewNode =NewNode (value); NewNode->next =head.load (); while(!head.compare_exchange_w

See cool shell http://coolshell.cn/articles/8239.html CAS is an implementation of lock-free, which forms an important basis for efficient concurrent containers of JDK concurrent packages. Therefore, read it carefully. Post-read notes Understanding of ABA: In dB, it is a common practice to change the value of the last modified time field in a row of records as a reference object when updating the records