Bubble (computing)

In computing

Computing

Computing is usually defined as the activity of using and improving computer hardware and software. It is the computer-specific part of information technology...

, a bubble is a "hiccup" in execution of an instruction

Instruction set

An instruction set, or instruction set architecture , is the part of the computer architecture related to programming, including the native data types, instructions, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O...

 in an instruction pipeline

Instruction pipeline

An instruction pipeline is a technique used in the design of computers and other digital electronic devices to increase their instruction throughput ....

.

The following is two executions of the same four instruction through a 4-stage pipeline but, for whatever reason, a delay in fetching of the purple instruction in cycle #2 leads to a bubble being created delaying all instructions after it as well.

Normal execution	Execution with a bubble