525 results about "Mutual exclusion" patented technology

A task management system that inherit priority and that can reduce the queue operation required for transition to/return from a mutual exclusion awaiting state The task management system can execute a task without considering its priority, start or stop a server task and inherit priority without operating the dispatch queue. The task management system includes activity retaining information, context retaining information, and a dispatch queue used to select the highest priority task. Information on a task is divided and managed by the activity and the context, where each activity is inserted into/deleted from the dispatch queue. When the priority of a task is inherited by another task, only the correspondence between activity and context is changed.

A method and several variants for using information about the scope of access of objects acted upon by mutual exclusion, or mutex, locks to transform a computer program by eliminating locking operations from the program or simplifying the locking operations, while strictly performing the semantics of the original program. In particular, if it can be determined by a compiler that the object locked can only be accessed by a single thread it is not necessary to perform the "acquire" or "release" part of the locking operation, and only its side effects must be performed. Likewise, if it can be determined that the side effects of a locking operation acting on a variable which is locked in multiple threads are not needed, then only the locking operation, and not the side effects, needs to be performed. This simplifies the locking operation, and leads to faster programs which use fewer computer processor resources to execute; and programs which perform fewer shared memory accesses, which in turn not only causes the optimized program, but also other programs executing on the same computing machine to execute faster. The method also describes how information about the semantics of the locking operation side effects and the information about the scope of access can also be used to eliminate performing the side effect parts of the locking operation, thereby completely eliminating the locking operation. The method also describes how to analyze the program to compute the necessary information about the scope of access. Variants of the method show how one or several of the features of the method may be performed.

Transactional Lock Elision (TLE) may allow multiple threads to concurrently execute critical sections as speculative transactions. Transactions may abort due to various reasons. To avoid starvation, transactions may revert to execution using mutual exclusion when transactional execution fails. Because threads may revert to mutual exclusion in response to the mutual exclusion of other threads, a positive feedback loop may form in times of high congestion, causing a “lemming effect”. To regain the benefits of concurrent transactional execution, the system may allow one or more threads awaiting a given lock to be released from the wait queue and instead attempt transactional execution. A gang release may allow a subset of waiting threads to be released simultaneously. The subset may be chosen dependent on the number of waiting threads, historical abort relationships between threads, analysis of transactions of each thread, sensitivity of each thread to abort, and/or other thread-local or global criteria.

Adaptive modifications of spinning and blocking behavior in spin-then-block mutual exclusion include limiting spinning time to no more than the duration of a context switch. Also, the frequency of spinning versus blocking is limited to a desired amount based on the success rate of recent spin attempts. As an alternative, spinning is bypassed if spinning is unlikely to be successful because the owner is not progressing toward releasing the shared resource, as might occur if the owner is blocked or spinning itself. In another aspect, the duration of spinning is generally limited, but longer spinning is permitted if no other threads are ready to utilize the processor. In another aspect, if the owner of a shared resource is ready to be executed, a thread attempting to acquire ownership performs a “directed yield” of the remainder of its processing quantum to the other thread, and execution of the acquiring thread is suspended.

Transactional Lock Elision (TLE) may allow threads in a multi-threaded system to concurrently execute critical sections as speculative transactions. Such speculative transactions may abort due to contention among threads. Systems and methods for managing contention among threads may increase overall performance by considering both local and global execution data in reducing, resolving, and/or mitigating such contention. Global data may include aggregated and/or derived data representing thread-local data of remote thread(s), including transactional abort history, abort causal history, resource consumption history, performance history, synchronization history, and/or transactional delay history. Local and/or global data may be used in determining the mode by which critical sections are executed, including TLE and mutual exclusion, and/or to inform concurrency throttling mechanisms. Local and/or global data may also be used in determining concurrency throttling parameters (e.g., delay intervals) used in delaying a thread when attempting to execute a transaction and/or when retrying a previously aborted transaction.

A queue-based spin lock with timeout allows a thread to obtain contention-free mutual exclusion in fair, FIFO order, or to abandon its attempt and time out. A thread may handshake with other threads to reclaim its queue node immediately (in the absence of preemption), or mark its queue node to allow reclamation by a successor thread.

A host system is provided with a shared resource (such as work queues and completion queues); multiple processors arranged to access the shared resource; and an operating system arranged to allow multiple processors to perform work on the shared resource concurrently while supporting updates of the shared resource. Such an operating system may comprise a synchronization algorithm for synchronizing multiple threads of operation with a single thread so as to achieve mutual exclusion between multiple threads performing work on the shared resource and a single thread updating or changing the state of the shared resource without requiring serialization of all threads.

The invention relates to the field of cloud storage, and discloses a method and a device for data synchronization based on a cluster server system. The method comprises the steps of dynamically electing a master node, and notifying the master node to process in a cluster after worker nodes receive a task, thereby effectively ensuring the data consistency, avoiding mutual exclusion and synchronization between processes of the nodes at the same time, and reducing the system overhead. According to the invention, the cluster server system comprises at least one cluster, the cluster comprises at least three nodes, and the method for data synchronization based on the cluster server system comprises the steps that one node in the cluster is dynamically elected as the master node, and the other nodes act as the worker nodes; if the worker nodes receive a task request, the other nodes in the cluster are notified to process the task; each of the other nodes in the cluster judges whether the node itself is the master node or not after receiving the notice; and if the node is the master node, the master node processes the task and feeds back a processing result.

Priority inheritance is implemented across a distributed system, preferably by use of a mutual exclusion object, referred to as a pseudo-mutex, which provides operations for communicating priority of a task which is held to a different connected processor or node of a network and generating a dummy local command of priority at least equal to that of the held task at the remote processor or node in collaboration with a real-time operating system and middleware. The remote real time operating system then carries out priority inheritance in the normal manner to raise the priority of a blocked task, thus reversing any preemption of that task at the remote processor or node. The increase in priority avoids preemption of lower priority processes and thus increases the execution speed of the executing thread to release the existing lock at an earlier time; allowing a lock to be obtained by the higher priority thread. The middleware serves as an intermediary, communicating messages that include pseudo-mutex arguments or similar communications and requests for enabling priority inheritance across nodes.

A system and method for merging two rulesets provided in rule-based systems associated with originating applications executing at different locations, each ruleset comprising rules in potential conflict with each other, and each ruleset being in a different rule format. The rulesets to be merged are communicated to an assimilator service provided with a merge policy comprising a set of specifications of partially-ordered priorities and/or mutual-exclusion constraints. The rulesets are translated into a common core representation capable of being implemented in any logic program rule engine provided in a rule-based application at any location. The rulesets are assimilated to produce a new merged ruleset comprising logic required for resolving potential conflicts among rules in accordance with the merge policy that is implemented in any logic program rule engine provided at any location. The new merged ruleset is then translated into one of the originating application's rule format.

The invention discloses a multi-modal man-machine interaction system and a control method thereof. The main interaction process comprises: interaction information collection, interaction motion identification, interaction instruction mapping, logic processing unit, and interaction motion response. The interactive identification algorithm of voice, touch gesture and body feeling and gesture is broken through. The method comprises contact dynamic tracking and movement track coupling algorithm, physical parameter model coupling method, multi-user interaction queue mechanism. Touch control / body feeling gesture interaction mapping instruction and logic processing, cooperation /mutual exclusion access mechanism are set; the user control instruction is converted into service instruction of application system scheduling execution; multi-user interaction is supported; the system has strong anti-interference capability and identification efficiency.

This invention teaches a way of implementing formally verified massively parallel programs, which run efficiently in distributed and shared-memory multi-core chips. It allows programs to be developed from an initial abstract statement of interactions among parallel software components, called cells, and progressively refine them to their final implementation. At each stage of refinement a formal description of patterns of events in computations is derived automatically from implementations. This formal description is used for two purposes: One is to prove correctness, timings, progress, mutual exclusion, and freedom from deadlocks/livelocks, etc. The second is to automatically incorporate into each application a Self-Monitoring System (SMS) that constantly monitors the application in parallel, with no interference with its timings, to identify and report errors in performance, pending errors, and patterns of critical behavior. This invention also teaches a way of organizing shared-memory for multi-processors that minimizes memory interference, protects data and increases execution efficiency.

A decentralized management model enables a plurality of interconnected modules to be managed and controlled as an integrated unit without requiring any one of the interconnected modules to operate as a fully centralized manager. One of the interconnected modules is configured to operate as a base module, which coordinates certain network management operations among the interconnected modules. Each of the interconnected modules is capable of sending and receiving management and control information. Each of the interconnected modules maintains a segmented management database containing network management parameters that are specific to the particular module, and also maintains a shadowed management database containing network management parameters that are common to all of the interconnected modules in the stack. Management and control operations that do not require synchronization or mutual exclusion among the various interconnected modules are typically handled by the module that receives a management/control request. Management and control operations that require synchronization or mutual exclusion among the various interconnected modules are handled by the base module.

The invention discloses a method for processing business conversational application with a multi-thread and a device thereof. The method comprises that a business conversational application program creates and activates a message delivery thread and a plurality of data processing threads in advance, and allocates a data area only associated with each data processing thread for each data processing thread; when receiving message from an external message entity, the message delivery thread only associates the business conversation of the message with one data processing thread, and deliveries the message to the data processing thread; when receiving the message delivered by the message delivery thread, the data processing thread performs the corresponding process to the corresponding data area according to the status of the message, and feeds back the processed result to the external message entity. The invention avoids the defects of synchronization and mutual exclusion mechanism, and greatly reduces the complexity of the system process while ensuring the safe and effective operation of the system.

A safety system receives access monitoring information from sensors to detect intrusion into a mutual exclusion zone by either an operator or mechanical equipment. The border of the mutual exclusion zone is segmented into portals that allow both the operator and equipment to access a common work area such as for loading material. When intrusion into one of the portals is detected, intrusion into any other selected portals triggers a safety violation. Access to the mutual exclusion zone via the other portals is prohibited until the interior of the zone is determined to be empty again.

A dual network card cooperative handover method based on a train position is characterized in that current position information of a train is obtained through two methods, namely information of all access points (AP) beside a track obtained by scanning through a vehicle-mounted single threaded apartment (STA) in an area is obtained through background scanning, and single-network-card fast active roaming handover of the vehicle-mounted STA is conducted by combining an AP information data base beside the track. Simultaneously, dual network cards cooperate to work through a mutual exclusion lock, the fact that at most only one network card performs roaming switching at the same moment is guaranteed, and at least one network card keeps reliable data transmission, thereby enabling the vehicle-mounted STA to provide a fast roaming handover function with zero handover time and zero packet loss for an upper-layer application system of the track, and achieving stable and reliable vehicle-ground data bidirectional transmission. Handover time of a handover algorithm is zero, and a phenomenon of losing packets caused by handover can not occur.

The invention provides a universal serial device communication module based on an Android system, which can realize calling to various serial devices under the Android system, and provides a solution for mutual exclusion produced when various (APK) application processes access to the same serial device at the same time. The universal serial device communication module is in operation on a Linux kernel and under an Android frame, and comprises a serial device drive layer, a hardware abstraction layer, a Framework layer and a JNI (Java Native Interface) layer. The universal serial device communication module provides convenience for the Android system to be applied in industries needing to call the serial devices.

A system for and method of implementing a backoff protocol and a computer network incorporating the system or the method. In one embodiment, the system includes: (1) a client subsystem that generates a request for access to a shared resource and (2) a server subsystem that receives the request, returns a LOCKED indicator upon an expectation that the shared resource is unavailable and otherwise returns a FREE indicator, the client subsystem responding to the LOCKED indicator by waiting before regenerating the request for the access.

A resource access control mechanism for a multi-threaded computing environment associates a sequence of one or more mutexes with a resource. When a requesting thread attempts to access the resource, a mutex is locked and allocated to the requesting thread, and if a previous mutex in the sequence is present, an attempt to lock the previous mutex is made. If the previous mutex is already locked, the requesting thread is suspended until the previous mutex is unlocked.

A system and associated method for mutually exclusively executing a critical section by a process in a computer system. The critical section accessing a shared resource is controlled by a lock. The method measures a detection time when a lock contention is detected, a wait time representing a duration of wait for the lock at each failed attempt to acquire the lock, and a delay representing a total lapse of time from the detection time till the lock is acquired. The delay is logged and used to calculate an average delay, which is compared with a suspension overhead time of the computer system on which the method is executed to determine whether to spin or to suspend the process while waiting for the lock to be released.

Send-side matching of data communications messages in a distributed computing system comprising a plurality of compute nodes organized for collective operations, including: issuing by a receiving node to source nodes a receive message that specifies receipt of a single message to be sent from any source node, the receive message including message matching information, a specification of a hardware-level mutual exclusion device, and an identification of a receive buffer; matching by two or more of the source nodes the receive message with pending send messages in the two or more source nodes; operating by one of the source nodes having a matching send message the mutual exclusion device, excluding messages from other source nodes with matching send messages and identifying to the receiving node the source node operating the mutual exclusion device; and sending to the receiving node from the source node operating the mutual exclusion device a matched pending message.