The market for portable devices, for example, mobile phones, smart watches, tablets, etc., is expanding with many more features and applications. As the number of applications on these devices increases, there also is an increasing demand to run multiple applications concurrently. More features and applications call for microprocessors to have high performance, but with low power consumption. Multithreading can contribute to high performance in this new realm of application. Keeping the power consumption for the microprocessor and related cores and integrated circuit chips near a minimum, given a set of performance requirements, is desirable, especially in portable device products.
Multithreading is the ability to pursue two or more threads of control in parallel within a microprocessor pipeline. Multithreading is motivated by low utilization of the hardware resource in a microprocessor. In comparison, multi-core is fairly wasteful of the hardware resource. Multithreading can, in general, provide the same performance as multicore without duplicating of resources.
Multithreading can be used in an effort to increase the utilization of microprocessor hardware and improve system performance. Multithreading is a process by which two or more independent programs, each called a “thread,” interleave execution in the same processor, which is not a simple problem. Each program or thread has its own register file, and context switching to another program or thread requires saving and restoring of data from a register file to a memory. This process can consume much time and power. These and other problems confront attempts in the art to provide efficient multithreading processors and methods.