One of the simplest primitives is called a test-and-set (“TAS”) instruction. Inter-thread (inter-process) synchronization in multithreaded programs is usually based on low-level functions supported by the hardware and called, aptly enough, synchronization primitives. G06F9/52- Program synchronisation Mutual exclusion, e.g.G06F9/46- Multiprogramming arrangements.using an internal store of processing equipment to receive or retain programs control units using stored programs, i.e. G06F9/06- Arrangements for program control, e.g.G06F9/00- Arrangements for program control, e.g.G06- COMPUTING CALCULATING OR COUNTING.Publication of US20070300226A1 publication Critical patent/US20070300226A1/en Application granted granted Critical Publication of US8434082B2 publication Critical patent/US8434082B2/en Status Expired - Fee Related legal-status Critical Current Adjusted expiration legal-status Critical Links Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.) Filing date Publication date Application filed by Intel Corp filed Critical Intel Corp Priority to US11/473,580 priority Critical patent/US8434082B2/en Assigned to INTEL CORPORATION reassignment INTEL CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Original Assignee Intel Corp Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.) Bliss Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.) Granted Application number US11/473,580 Other versions US8434082B2 Google Patents Efficient ticket lock synchronization implementation using early wakeup in the presence of oversubscriptionĭownload PDF Info Publication number US20070300226A1 US20070300226A1 US11/473,580 US47358006A US2007300226A1 US 20070300226 A1 US20070300226 A1 US 20070300226A1 US 47358006 A US47358006 A US 47358006A US 2007300226 A1 US2007300226 A1 US 2007300226A1 Authority US United States Prior art keywords value ticket polling thread memory location Prior art date Legal status (The legal status is an assumption and is not a legal conclusion. Google Patents US20070300226A1 - Efficient ticket lock synchronization implementation using early wakeup in the presence of oversubscription The Node QNode in the CLH queue contains a Locked field that indicates that the thread needs to get the lock if true, and does not release the lock, and the thread releases the lock to FALSE.US20070300226A1 - Efficient ticket lock synchronization implementation using early wakeup in the presence of oversubscription The code posted in this is the primary process code, the detailed code is GitHubin. Next, let's talk about the Java implementation of this algorithm. Waiting for the thread as the node in the queue acquires the lock. With the help of a CAS operation, all the nodes waiting for the thread wait for the lock easily and correctly built a global queue. If the predecessor releases the lock, the spin is completed. At the same time, it is also an extensible, high-performance, fair spin lock based on the list, and the application thread is only spin on the local variable, which continuously polls the state of the forefront. We can see it is a spin lock that ensures un hungry, providing the first time to serve the fairness. If it is found that the pre release lock end spin. The application thread spin only on a local variable, it constantly polling the precursor state, The CLH lock is a scalable, high performance, fairness and spin lock based on the list, CLH lock is Craig, Landin, and Hagersten (CLH) locks,ĬLH lock is a spin lock, can ensure no hunger, provide fairness first come first service. Papers address Of the CLH: Craig, Landin, And Hagersten. I can find a lot of blogs about CLH on the Internet, but it is better to comprehensively, so I have to organize a clear point. In order to better understand the idea of using the lock in AQS, I decided to understand the CLH lock first. I believe that most people can see the comments on the comment when watching AQS: The wait queue is a variant of a "CLH" (Craig, Landin, and Hagersten) lock queue. Why do you have mypred, don't you do it?.How to understand the SET operation in UNLOCK?.Why use ThreadLocal to save MYNODE and MyPred?.The first thread using the CLHLOCK is automatically acquired to the lock.
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