Computer Architecture Questions
Instruction level parallelism (ILP) refers to the ability of a computer architecture to execute multiple instructions simultaneously or out of order, in order to improve performance and increase the overall throughput of the system.
ILP is achieved by identifying and exploiting independent instructions that can be executed concurrently, even though they are part of a sequential program. This is done by analyzing the dependencies between instructions and determining which instructions can be executed in parallel without affecting the correctness of the program.
There are several techniques used to exploit ILP, including instruction pipelining, superscalar execution, and out-of-order execution. Instruction pipelining divides the execution of instructions into multiple stages, allowing different stages to work on different instructions simultaneously. Superscalar execution enables the execution of multiple instructions in parallel by having multiple functional units within the processor. Out-of-order execution reorders the instructions dynamically to maximize the utilization of available resources and minimize stalls.
By leveraging ILP, computer architectures can achieve higher performance by effectively utilizing the available hardware resources and reducing the impact of dependencies between instructions. However, the effectiveness of ILP is limited by factors such as data dependencies, control dependencies, and resource constraints.