Various technologies and techniques are disclosed for providing software accessible metadata on a cache of a central processing unit. A multiprocessor has at least one central processing unit. The central processing unit has a cache with cache lines that are augmented by cache metadata. The cache metadata includes software-controlled metadata identifiers that allow multiple logical processors to share the cache metadata. The metadata identifiers and cache metadata can then be used to accelerate various operations. For example, parallel computations can be accelerated using cache metadata and metadata identifiers. As another example, nested computations can be accelerated using metadata identifiers and cache metadata. As yet another example, transactional memory applications that include parallelism within transactions or that include nested transactions can be also accelerated using cache metadata and metadata identifiers.