Multithreaded processor for image generation

Multiple instruction execution is a major approach to designing high-performance processors. Superscalar and VLIW processor that utilize instruction level parallelism are usually focused on. On the other hand, the multithreaded processor can be expected to achieve a high degree of multiple instruction execution by utilizing coarse grain parallelism. Many computer graphics applications (such as the radiosity method and ray-tracing method) can be optimized by reorganizing the code to take advantage of coarse grain parallelism, but the degree of instruction level parallelism is not sufficient for a superscalar processor. Experimental result using the radiosity method shows that the 4-thread multithreaded processor achieves 2.9 times speedup over single thread, while the 4-issue superscalar processor manages around 1.5 times. By duplicating two kinds of function units, the performance of a multithreaded processor increases to 3.7 times, but the performance of a superscalar processor is saturated at around 1.5 times. Therefore, for computer graphics applications, the multithreaded processor is a better approach than the superscalar processor