Re: [Lse-tech] [patch] sched-domain cleanups, sched-2.6.5-rc2-mm2-A3

[Nick Piggin <nickpiggin@yahoo.com.au>]

Ingo Molnar wrote:
> * Nick Piggin <nickpiggin@yahoo.com.au> wrote:
> 
> 
>>>This works much better, but wildly varying (my tests go from 2.8xCPU to 
>>>~3.8x CPU for 4 CPUs. 2,3 CPU cases are ok). A bit more consistent 
>>>results would be better though.
>>
>>Oh good, thanks Ingo. Andi you probably want to lower your minimum
>>balance time too then, and maybe try with an even lower maximum. Maybe
>>reduce cache_hot_time a bit too.
> 
> 
> i dont think we want to balance with that high of a frequency on NUMA
> Opteron. These tunes were for testing only.
> 

I guess not. Andi says he wants it more like UMA balancing though...


> i'm dusting off the balance-on-clone patch right now, that should be the
> correct solution. It is based on a find_idlest_cpu() function which
> searches for the least loaded CPU and checks whether we can do passive
> load-balancing to it. Ie. it's yet another balancing point in the
> scheduler, _not_ some balancing logic change.
> 

Yep, as I said to Martin, I also agree this is probably good if it
is done carefully. I think we'll need to get a horde of thread
benchmarking people together before turning it on by default, of
course.

It seems Andi can now get equivalent results without it now, so it
isn't a pressing issue.