基于ROACH2-GPU集群相关器的研究--F-engine模块的设计与实现

Research on the ROACH2-GPU-Cluster-Based Correlator——Design and Implementation of an F-engine Model

相关器在射电天文中具有重要作用。以往的相关器多采用现场可编程门阵列(Field-Programmable Gate Array,FPGA)或者特定用途集成电路(Application Specific Integrated Circuit,ASIC)技术,开发周期长,不便扩展和改进升级。近年来许多新研制的射电干涉阵相关器采用具有通用架构的现场可编程门阵列和图形处理器的相关器。针对暗能量射电探测实验(天籁计划)的需求,开发了一套基于可重构开放架构计算硬件(Reconfigurable Open Architecture Computing Hardware,ROACH2)和图形处理器的异构相关器,将相关器的数据采集、快速傅里叶变换(Fast Fourier Transform,FFT)等功能与复数乘累加运算功能分开,充分利用了现场可编程门阵列的硬件资源和图形处理器的运算速度。该相关器易于扩展,且运算负载可根据实际运算能力进行不同节点的分配,非常灵活。目前已经应用到天籁计划项目中。

Correlator plays an important role in radio interferometry astronomy. Traditional correlator is achieved with FPGA or ASIC. It calls for long development cycle and its flexibility is unsatisfactory. At present, more and more radio astronomy arrays adopt generic architecture correlator with FPGA system and GPU. In order to meet the demands of the ＇Tianlai＇ project, we developed a new correlator based on ROACH2 and GPU cluster. We divided the workflow of the correlator into two parts： we let the high performance GPU undertake the CMAC （conjugate multiply and accumulate ） and only left the ADC and FFT for the F-engine. This correlator has high flexibility and it is easy to control. It has been applied to the Tianlai project.