To get maximum parallelization for an application, not only must the application be developed to take advantage of multiple cores, but should also have the code in place to keep a number of threads working on each core. A modern processor architecture, such as the Intel Xeon Phi processor, can accommodate at least 4 threads for each core. “On the Intel Xeon Phi processor, each of the threads per core is known as a hyper-thread. In this architecture, all of the threads on a core progress through the pipeline simultaneously, producing results much more quickly than if just one thread was used. The processor decides which thread should progress, based on a number of factors, such as waiting for data from memory, instruction availability, and stalls.”
Intel Xeon Phi Processor: A Look at the Basic Architecture
“Designing a new generation of hardware with such high performance needs to make sure that developers understand the basics, and are familiar with the architecture of a new system. Single thread performance with the Intel Xeon Phi processor is significantly better than previous designs. In addition, in order to speed up performance even more, vector processing, where applicable is critical in application performance. With two vector processing units (VPUs) per core, applications can execute two 512-bit vector multiply-add instructions per cycle. Each of these cores can deliver 32 double precision operations per clock cycle. The VPU executes all of the floating point operations as well as legacy instructions from SSE to AVX to the new AVX-512 instructions.”
