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A lock-free data structure can be used to improve performance. A lock-free data structure increases the amount of time spent in parallel execution rather than serial execution, improving performance on a multi-core processor, because access to the shared data structure does not need to be serialized to stay coherent. [4]
Two-handed emulation: how to build non-blocking implementations of complex data-structures using DCAS, Michael Greewald; Highly-Concurrent Multi-word Synchronization, Hagit Attiya, Eshcar Hillel; Lock-free deques and doubly linked lists, Håkan Sundell, Philippas Tsigas
MemSQL uses lock-free skip lists as its prime indexing structure for its database technology. MuQSS, for the Linux kernel, is a CPU scheduler built on skip lists. [10] [11] Cyrus IMAP server offers a "skiplist" backend DB implementation [12] Lucene uses skip lists to search delta-encoded posting lists in logarithmic time. [citation needed]
Java provides the keyword synchronized to lock code blocks, methods or objects [11] and libraries featuring concurrency-safe data structures. Objective-C provides the keyword @synchronized [ 12 ] to put locks on blocks of code and also provides the classes NSLock, [ 13 ] NSRecursiveLock, [ 14 ] and NSConditionLock [ 15 ] along with the ...
In many situations it is possible to design data structures that do not require locking, e.g. by using per-thread or per-CPU data and disabling interrupts. Switch to a different thread while waiting. This typically involves attaching the current thread to a queue of threads waiting for the lock, followed by switching to another thread that is ...
Any lock-free data structure that uses the compare-and-swap primitive must deal with the ABA problem. For example, in a lock-free stack represented as an intrusively linked list, one thread may be attempting to pop an item from the front of the stack (A → B → C).
STM can be implemented as a lock-free algorithm or it can use locking. [7] There are two types of locking schemes: In encounter-time locking (Ennals, Saha, and Harris), memory writes are done by first temporarily acquiring a lock for a given location, writing the value directly, and logging it in the undo log.
The shared resource is a data object, which two or more concurrent threads are trying to modify (where two concurrent read operations are permitted but, no two concurrent write operations or one read and one write are permitted, since it leads to data inconsistency). Mutual exclusion algorithms ensure that if a process is already performing ...