1.3 Speculative Way Selection
The basic idea of speculative way activation is to make a prediction
of the way where the required data may be located. If the
prediction is correct, the cache access latency and power consumption is similar to that of a direct-mapped cache of the same size. If
the prediction is wrong, the cache is accessed again to retrieve the
desired data. The cache is accessed as a direct-mapped cache twice.
Because of high prediction accuracy, proposed designs have saved
both time and power. Some designs have also been industrialized.
Prior work can be categorized by the way the cache is probed.