Transactional memory (TM) is a promising alternative to mutual exclusion. In spite of this, it may be unrealistic for TM programs to be devoid of locks due to their abundant use in legacy software systems. Consequently, for TMs to be practical they may need to manage the interaction of transactions and locks when they access the same shared-memory. This paper presents two algorithms, one coarse...

Optimistic methods of concurrency control are gaining popularity. This is especially true with the resurgence of mobile and distributed databases, which inherently rely on optimistic techniques to improve availability and performance of the database system. A key problem with optimistic techniques is that they do not perform well in highly conflict prone environments. Pessimistic techniques, es...

Large-scale shared-memory multiprocessors typically have long latencies for remote data accesses. A key issue for execution performance of many common applications is the synchronization cost. The communication scalability of synchronization has been improved by the introduction of queue-based spin-locks instead of Test&(Test&Set). For architectures with long access latencies for global data, a...

Transactional memory (TM) has garnered significant interest as an alternative to existing concurrency methods due to its simplified programming model, natural composition characteristics and native support of optimistic concurrency. Yet, mutual exclusion locks are ubiquitous in existing parallel software due to their fast execution, inherent property for irreversible operations and long-standin...

We present a resource oriented program logic that is able to reason about concurrent heap-manipulating programs with unbounded numbers of dynamically-allocated locks and threads. The logic is inspired by concurrent separation logic, but handles these more realistic concurrency primitives. We demonstrate that the proposed logic allows local reasoning about programs for which there exists a notio...

A challenge for programming language research is to design and implement multi-threaded low-level languages providing static guarantees for memory safety and freedom from data races. Towards this goal, we sketch a concurrent language employing safe region-based memory management and hierarchical locking of regions. Both regions and locks are treated uniformly, and the language supports ownershi...

In database systems, users access shared data under the assumption that the data satisfies certain consistency constraints. This paper defines the concepts of transaction, consistency and schedule and shows that consistency requires that a transaction cannot request new locks after releasing a lock. Then it is argued that a transaction needs to lock a logical rather than a physical subset of th...

Storing, querying, and updating XML documents in multi-user environments requires data processing guarded by a transactional context to assure the well-known ACID properties, particularly with regard to isolate concurrent transactions. In this paper, we introduce the taDOM tree, an extended data model which considers organization of both attribute nodes and node values in a new way and allows f...

CPHASH is a concurrent hash table for multicore processors. CPHASH partitions its table across the caches of cores and uses message passing to transfer lookups/inserts to a partition. CPHASH’s message passing avoids the need for locks, pipelines batches of asynchronous messages, and packs multiple messages into a single cache line transfer. Experiments on a 80-core machine with 2 hardware threa...

Ajlatoxin contamination of cottonseedfrom bolls damaged by the pink bollworm (PB W) ,Pectinophora gossypiella (Saunders) , was comparedwith contamination ofcottonseedfrom undamaged bolls. Test bolls for comparative studies were collectedfrom similar positions on 25 plants in each ofthree harvests during a single season. Cottonseedproduced in PBW-damaged bolls were the predominant source ofajlat...