A gather/scatter hardware support for efficient Fast Fourier Transform

The increase of operating frequency of microprocessors has begun to meet more obstacles. Performance of single-thread applications no longer benefits from running under a faster processor. As a result, the performance increase has to come from additional hardware support which makes use of the large number of transistors available. This paper presents a novel hardware support called distTree to speed up processor performance. The distTree hardware automates gather and scatter operations for applications with complex but predictable memory access patterns like the Fast Fourier Transform (FFT). With this hardware support integrated with a modern microprocessor like Alpha, the FFT performance can reap an increase of over 100% when compared against the FFTW library, a state-of-the-art implementation. The distTree hardware support enables the processor to spend the majority of processor cycles on executing the computation operations of an algorithm by reducing both the arithmetic and address computation overhead. Therefore, the performance of many single-thread applications can be significantly increased.