Binary Search Tree (BST) is an important data structure for managing ordered data. Many algorithms---blocking as well as non-blocking---have been proposed for concurrent manipulation of a binary search tree in an asynchronous shared memory system that supports search, insert and delete operations based on both external and internal representations of a search tree.

We present a new lock-based algorithm for concurrent manipulation of a binary search tree in an asynchronous shared memory system that supports search, insert and delete operations. Some of the desirable characteristics of our algorithm are: (i) a search operation uses only read and write instructions, (ii) an insert operation does not acquire any locks, and (iii) a delete operation only needs to lock up to four edges in the absence of contention. Our algorithm is based on an internal representation of a search tree and it operates at edge-level (locks edges) rather than at node-level (locks nodes); this minimizes the contention window of a write operation and improves the system throughput. Our experiments indicate that our lock-based algorithm outperforms existing algorithms for a concurrent binary search tree for medium-sized and larger trees, achieving up to 59% higher throughput than the next best algorithm.

NAS parallel benchmarks (NPB) are a set of applications commonly used to evaluate parallel systems. We use the NPB-OpenMP version to examine the performance of the Intel's new Xeon Phi co-processor and focus in particular on the many core aspect of the Xeon Phi architecture. A first analysis studies the scalability up to 244 threads on 61 cores and the impact of affinity settings on scaling. It also compares performance characteristics of Xeon Phi and traditional Xeon CPUs. The application of several well-established optimization techniques allows us to identify common bottlenecks that can specifically impede performance on the Xeon Phi but are not as severe on multi-core CPUs. We also find that many of the OpenMP-parallel loops are too short (in terms of the number of loop iterations) for a balanced execution by 244 threads. New or redesigned benchmarks will be needed to accommodate the greatly increased number of cores and threads. At the end, we summarize our findings in a set recommendations for performance optimization for Xeon Phi.