Messages in this thread | | | Date | Thu, 23 Jul 2009 15:17:18 -0700 | Subject | Re: CFS group scheduler fairness broken starting from 2.6.29-rc1 | From | Ken Chen <> |
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On Thu, Jul 23, 2009 at 12:57 AM, Bharata B Rao<bharata@linux.vnet.ibm.com> wrote: > Hi, > > Group scheduler fainess is broken since 2.6.29-rc1. git bisect led me > to this commit: > > commit ec4e0e2fe018992d980910db901637c814575914 > Author: Ken Chen <kenchen@google.com> > Date: Tue Nov 18 22:41:57 2008 -0800 > > sched: fix inconsistency when redistribute per-cpu tg->cfs_rq shares > > Impact: make load-balancing more consistent > .... > > ====================================================================== > % CPU time division b/n groups > Group 2.6.29-rc1 2.6.29-rc1 w/o the above patch > ====================================================================== > a with 8 tasks 44 31 > b with 5 tasks 32 34 > c with 3 tasks 22 34 > ====================================================================== > All groups had equal shares.
What value did you use for each task_group's share? For very large value of tg->shares, it could be that all of the boost went to one CPU and subsequently causes load-balancer to shuffle tasks around. Do you see any unexpected task migration?
- Ken
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