Messages in this thread | | | Date | Mon, 17 Nov 2008 15:19:20 -0600 | From | "Chris Friesen" <> | Subject | Re: busted CFS group load balancer? |
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Ken Chen wrote: > On Mon, Nov 17, 2008 at 7:37 AM, Chris Friesen wrote: >>> It appears that the fair-group load balancer in 2.6.27 does not work >>> properly. >> There was an issue fixed post 2.6.27 where the load balancer didn't work >> properly if there was one task per group per cpu. You might try >> backporting commit 38736f4 and see if that helps. > > Tested git commit 38736f4, it doesn't fix the problem I'm seeing. >
I plugged in the same weights into my test app (groups 1 and 2 instead of ant/bee) and got the results below for a 10-sec run. The "actual" numbers give the overall average and then the values for each hog separately. In this case we see that both tasks in group 2 ended up sharing a cpu with one of the tasks from group 1.
group actual(%) expected(%) ctx switches max_latency(ms) 1 99.69(99.38/99.99) 99.81 160/262 4/0 2 0.31( 0.31/0.31) 0.19 32/33 391/375
I've only got a 2-way system. If the results really are that much worse on larger systems, then that's going to cause problems for us as well. I'll see if I can get some time on a bigger machine.
Chris
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