Comment 32 for bug 999755

Unfortunately I was not yet able to pinpoint exactly the code that is wrong. But I think I know a way that can be used as a work-around until I find out the real fix. It looks very much like the problem is related to the autogroup feature which will automatically put tasks in separate task groups based on the session ids. The ohai process is doing this a lot, so I think compared to other work-loads there is a high volume of coming and going task groups, which might be the problem.

At the cost of loosing the fairer scheduling which isolation of high cpu using tasks in their own group brings, it is possible to disable the autogroup feature by either using "noautogroup" as pvgrub kernel argument, or changing
/proc/sys/kernel/sched_autogroup_enabled to 0. I guess that can be a sysctl entry, too. That way the ohai reproducer seems to survive, so production systems won't crash all the time (hopefully).