Types of Pipeline in Computer Architecture

Types of Pipeline in Computer Architecture – A pipeline can be visualized as a collection of processing hardware units through which the information or data flows. Each hardware unit performs partial processing dictated by the way the task is partitioned. The final result is obtained after the information or data has passed through all units. There are several ways to classify the pipeline; two of them are as follows:

Pipeline Types in Computer Architecture

1. Static and Dynamic Pipeline.
2. Arithmetic and Instruction Pipeline.

Static and Dynamic Pipeline

As the name suggests, a static pipeline can perform one operation at a time, and its operation can be changed after the pipeline has completed its previous operation. It means that while the pipeline is not drained, it can not be refilled.

For example, a pipeline can perform two operations: addition and multiplication. Each time the pipeline switches from one operation to another, it must be drained and set for the new operation. In a case when the operations change often, the performance of the static pipeline is severely degraded. The reason behind this is that every change in operation requires the pipeline to be drained and refilled each time. This makes the system slower.

A dynamic pipeline can perform many operations at a time. In dynamic pipelining, to perform a particular operation, the data has to go through a certain sequence of stages. The figure shows the 3 stages of the dynamic pipeline. This pipeline can perform addition and multiplication on different data at the same time.

As shown in the above figure, the multiplication operation is performed by passing the data through all stages. To perform the addition operation, the data only needs to go through stages 1 and 3. Therefore, the first stage of the addition operation can be performed on input data at storage 1, while at the same time, the last stage of the multiplication process is performed at stage 3 on a different input data.

Arithmetic and Instruction Pipeline

The design principles for arithmetic and instruction pipelines are quite different. An arithmetic pipeline divides an arithmetic operation into sub-operations for execution in the pipeline segments. It is more useful for vector processing. An instruction pipeline operates as a stream of instructions by overlapping the fetch, decode, and execute phases of the instruction cycle. It tends to be more useful for computers with a simplified instruction set, as in RISC architecture. These two types of pipelines are explained in the following articles.

1. Arithmetic Pipeline
2. Instruction Pipeline

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