thread-local-storage (hackage): Thread-local storage, or TLS, is an important ingredient in many algorithms and data structures.  The GHC compiler does not provide a built-in notion of TLS either at the IO-thread or OS thread level.  This package provides a few different implementations of a simple TLS API.  All exported public modules provide exactly the same interface with different implementations.  Run the included criterion benchmark suite to ascertain which performs the best on your platform.  Example criterion benchmark data can be found here (from an Intel Ivy-Bridge i7-3770 desktop): http://www.cs.indiana.edu/~rrnewton/datasets/xmen_tls_report.html
Keywords: bsd3|library|system