Stencil operations are an important class of scientific computational kernels that are pervasive in scientific simulations as well as in image processing. A key characteristic of this class of computation is that they have a low operational intensity, i.e., the ratio of the number of memory accesses to the number of floating point operations it performs is high. As a result, the performance of ...

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Most multiprocessors are multiprogrammed in order to achieve acceptable response time and to increase their utilization. Unfortunately, inopportune preemption may significantly degrade the performance of synchronized parallel applications. To address this problem, researchers have developed two principal strategies for concurrent, atomic update of shared data structures: (1) preemption-safe loc...

We present an efficient and practical lock-free implementation of a concurrent priority queue that is suitable for both fully concurrent (large multi-processor) systems as well as pre-emptive (multi-process) systems. Many algorithms for concurrent priority queues are based on mutual exclusion. However, mutual exclusion causes blocking which has several drawbacks and degrades the overall perform...

We present an efficient and practical lock-free implementation of a concurrent priority queue that is suitable for both fully concurrent (large multi-processor) systems as well as pre-emptive (multi-process) systems. Many algorithms for concurrent priority queues are based on mutual exclusion. However, mutual exclusion causes blocking which has several drawbacks and degrades the system’s overal...

This work analyses a multiprocessor system in which processes communicate with each other via buffers using SEND and WAIT operations. Since the buffers are of finite capacity, a process which cannot execute a synchronisation operation successfully must leave the processor and go into the blocking state. The analysis of the multiprocessor system is executed hierarchically using two models (Globa...

heavy precipitation plays a significant role in arid and semi-arid regions of iran. in order to understand the effect of blocking high system on rainfalls in northwest iran during 25 - 28 october 2008, meteorological conditions including pressure, wind fields and temperature at multiple levels of the atmosphere were analyzed. sea level pressure, the 1000-500 hpa thickness, perceptible water, re...

since 20th  century, when allergy was defined, an ongoing attempt for discovering the mechanisms underlying it and its treatment began. defining allergens as well as cells such as regulatory t-cells and characterizing the antibodies involved in the pathogenesis (including blocking antibodies) have helped very much towards a better understanding of the immunologic process.however, allergen speci...