Comment 19 for bug 381300

After seeing a discussion at http://lkml.org/lkml/2009/9/19/288, I tried the patch to disable NEW_FAIR_SLEEPERS on 2.6.31-1 [ie change kernel/sched_features.h to include SCHED_FEAT(NEW_FAIR_SLEEPERS, 0) instead of SCHED_FEAT(NEW_FAIR_SLEEPERS, 1)].

It made a huge difference desktop responsiveness with heavy I/O using CFQ. I even loaded up the system with VMs so it was using all 4GB of RAM and 800MB or so of swap and the desktop remained usable - previously under those conditions, the system would invariably become unresponsive, even freezing entirely for ten minutes or more at a time.

The solution isn't perfect, though - it does reduce my test game frame rates by between 10% and 40%.