pcu is a set of simple command-line utilities to expose the posix_fadvise and mincore syscalls. pcu-fadvise gives the kernel advice on the access pattern for files. This advice can affect all processes by all users accessing those files. pcu-mincore is used to determine which parts of a file are in cache. These utilties are targeted for Linux 2.6, but may work on other operating systems that support the mincore and posix_fadvise syscalls. mincore is not a part of POSIX, and posix_fadvise is uncommon despite being specified by POSIX.
libnodelay is an LD_PRELOAD library for disabling Nagle's algorithm. Disabling Nagle's algorithm can result in a performance improvement for latency-sensitive applications that use TCP. Using the library may be easier than digging through a mess of code and confusing or obscure configuration options.
mmq plays arbitrary audio files gaplessly and continuously without needing a predefined queue. mmq is an exercise in minimalism, so it is more about avoiding needless features than anything else. mmq may be used standalone or managed by a larger application. mmq is only configurable at build time. Currently, FLAC decoding and SALSA-lib audio output support are implemented.