Comment 495 for bug 500069

Lets summarize the bugs.

- High cache usage during write process enforce swapping of processes
  Patch in comment #160 works, but is not included in the linux tree.

- Fsync Bug in Ext3
  (There is a test case and a activity)

- Too high prioritization of heavy writing processes
  (Copying a big file, can delay the start of a program till finishing the copy
   operation)

- Missing read and write based scheduler

And finally the annoying bugs
- Low gui responsiveness during heavy IO
  A reliable test case is still missing.
  - The test case in comment #311 shows high click latencies 2-12s
    during heavy io on non smp kernels
    (on smp kernels too, but it's not easy to catch such an event)
  - I have a socket ping pong test (not submitted), which shops latencies of
    ~2s after the writing processes are finished

- Low gui responsiveness in virtual machines
  no test case
  maybe the same bug as the "Low gui responsiveness during heavy IO" bug

The gui responsiveness are not deterministic, as there may be a day with nearby no latencies and a hour with continuous latencies up to 60 seconds