Sprungvorhersage

Sprungvorhersage, also known as jump prediction, is a technique used in computer architecture, specifically within pipelined processors, to improve performance. Pipelining allows a processor to execute multiple instructions concurrently by dividing the instruction execution into several stages. However, control flow changes, such as conditional branches, can disrupt this flow. When a branch instruction is encountered, the processor needs to decide whether to take the branch or not. If it makes the wrong prediction and starts executing instructions from the wrong path, it must discard the work done and restart from the correct path, leading to a performance penalty known as a pipeline stall.

Sprungvorhersage aims to minimize these stalls by predicting the outcome of a branch instruction before it is actually executed. Various prediction schemes exist, ranging from simple static predictors that always predict taken or not taken, to more complex dynamic predictors that learn from the past behavior of branches. Dynamic predictors often use history tables or pattern matchers to make more accurate predictions. The effectiveness of a sprungvorhersage unit is measured by its prediction accuracy. Higher accuracy leads to fewer pipeline stalls and thus higher overall processor performance. Modern processors employ sophisticated branch prediction mechanisms to achieve very high prediction accuracies, often exceeding 90%.