When IBM adds features and performance improvements to its mainframes' general purpose main processors (which can also run Linux), those features and improvements nearly always apply equally to IFLs.
In fact, in recent IBM Z machines IFLs support simultaneous multithreading, a feature not available for general purpose processors.
At the same time, IBM introduced a special Linux-only, VM-like product called the S/390 Virtual Image Facility for Linux to cater to IT staff previously unfamiliar with IBM mainframes.
IFLs also support select IBM software appliances such as the IBM Db2 Analytics Accelerator, zAware, and z/VSE Network Appliance, and they also supported the Z port of the now abandoned OpenSolaris operating system.
On Power Systems IFLs are also specially priced for both the processors and many software products.