DSB Switches

Metric Description

Intel® microarchitecture code name Sandy Bridge introduces a new decoded ICache. This cache, called the DSB (Decoded Stream Buffer), stores uOps that have already been decoded, avoiding many of the penalties of the legacy decode pipeline, called the MITE (Micro-instruction Translation Engine). However, when control flows out of the region cached in the DSB, the front-end incurs a penalty as uOp issue switches from the DSB to the MITE. This metric measures this penalty.

Possible Issues

A significant proportion of cycles are spent switching from the DSB to the MITE. This may happen if a hot region of code is too large to fit in the DSB. Consider changing code layout (for example, via profile-guided optimization) to help your hot regions fit in the DSB.

For more complete information about compiler optimizations, see our Optimization Notice.