Research And Implement Of Conditional Stream In X Stream Processor

The stream programming model casts applications as a set of sequential data streams that are operated on by data-parallel computation kernels. Previous work has shown that this model is a powerful representation for media processing applications, because it captures the locality and concurrency inherent to an application. And, the stream model can be implemented with efficient VLSI designs, such as the Imagine Programmable Stream Processor. But executing kernels with conditional code in Imagine is a challenge. Conditional stream can convert control-dependence to data-routing ,extending the range of applications that a data-parallel architecture can execute efficiently.The performance of the X stream processor with conditional stream can be improved obviously.The main goal of our work is the design and implementation of conditional stream based on stream architecture in order to make stream processor execute applications with data-dependent control flow.And through our work ,we can develop a platform and provide a basic hardware and software environment for architecture researcher,on which they can research the stream processor more deeply.We firstly study the process of conditional stream based on an example about conditional output stream,according to it,analyse the functional parts and the state which conditional stream needs.Secondly,we design the pipeline architecture of all fuctional parts and show the detailed logic.According to the function of all parts,we analyse an example detailedly.We implement two styles of if_else statement with conditional stream and compare it with the implement without conditional stream.We find that conditional stream has much more advantage,for conditional stream improve the performance by 2X in theory.But as to the stall inevitably ,the speed-up may be under 2.Experimental data show that in fact conditional stream can improve the performance by 1.8X on average.At last we evaluate the power,area and critical path of conditional stream ,which is the small part of the whole Cluster ,but can improve the performance efficiently.In other words,conditional stream is an useful mechanism.