Small collection of benchmarks for storage I/O - Version 3.6

This suite evaluates:
- responsiveness, by measuring start-up times of real applications
  under configurable background workloads
- latency for soft real-time applications, by measuring playback
  quality (drop rate) of video and audio under configurable background
  workloads
- speed of code-development tasks (make, git checkout, git merge, git
  grep) under configurable background workloads, plus responsiveness
  while one of these dev tasks is executed
- minimum per-client bandwidth guaranteed to a set of clients doing
  configurable types of I/O
- maximum per-client latency guaranteed to a set of clients doing
  configurable types of I/O
- throughput with processes doing filesystem or raw I/O in parallel
  (figure of merit measured by many other suites too)
- throughput with processes doing interleaved I/O, which mimics the
  typical I/O pattern of applications like qemu
- efficiency of block layer and I/O schedulers in terms of maximum
  number of IOPS supported (this functionality makes it easy to
  profile the desired component of the block layer)

See USAGE-INSTALLATION for all details. In particular, that file
also contains a quick but complete example of use.