A pipeline stall is a type of error in a RISC or RISC-influenced processor and it delays the processing of an instruction. This type of error isn’t anything to do with user errors – as a matter of fact, this type of error happens only because of processor design. More precisely, it occurs in poorly designed processors. RISC-type processors use pipelines, which means that instructions need to be executed in a specific order.
Technipages Explains Pipeline Stall
This specific order is absolute and very precise – if a program gives a branching instruction, then they aren’t presented in an orderly fashion – instructions at the beginning work their way through the pipeline, but options that weren’t selected have to be discarded before the next ones can be processed. This generates a delay and one based on the complexity of the branches at that. More discarded options means more of a delay, and the bigger the delay, the bigger the lag in performance.
This issue is unique to RISC-based processors, as others employ different setups. These errors aren’t fatal though – after their discovery, workarounds were created and implemented. Small delays can be eliminated entirely, while bigger ones can be reduced, at the very least. This is done through branch prediction, and eventually, the implementation of out-of-order execution for certain types of processes. These new features helped maintain the viability of RISC-type processors, despite the initial design flaws of reduced instruction set computers, despite their initial purpose having been a computer that can process instructions faster by skipping unnecessary steps.
Common Uses of Pipeline Stall
- Pipeline stalls are entirely design-flaw caused and aren’t influenced by user issues.
- In order to resolve pipeline stalls, branch prediction was implemented.
- The downside of RISC-processors was the potential of pipeline stalls.
Common Misuses of Pipeline Stall
- Pipeline stalls are caused by a user executing too many functions at once.
