Hi Jesse and Xavier,

  Since last February we have implemented a patch for Linux that 
considers the number of levels a NUMA computer has. We build the sched 
domains based on the number of levels, which we extract from the SLIT 
table. We have tested our code on a HP Superdome computer, and we are 
willing to share it with someone that would try it. We didn't share it 
before because we could not test our patch in a bigger machine. The 
machine we have access to is a 1 NUMA level.

  Further, we modelled our strategy using analytical models and 
simulation and the results we got are promissing. You can find our patch 
and copies of two papers that describe our strategy in the following 
address:  http://www.inf.pucrs.br/~peso/loadBalancerEng.htm. We are 
preparing a paper on the simulation results we got (if you would like to 
get a copy of the unfinished version of this paper, we can send it 
directly to you).

  It would be nice if you could give us some feedback on our approach.

  Monica Correa

Jesse Barnes wrote:

>On Friday, May 27, 2005 8:57 am, Xavier Bru wrote:
>  
>
>>An other alternative is using the node_distance() that comes from the
>>SLIT to build the sched domains instead of using
>>SD_NODES_PER_DOMAIN on the platform.
>>    
>>
>
>This option seems like the way to go.  The size is far from optimally 
>tuned as well, benchmarking is needed (unless we want boot time 
>heuristics to determine the sched domain layout).
>
>  
>
>>The following patch sets SD_NODES_PER_DOMAIN as a config/boot
>>parameter, and when the value is 0 uses the node_distance to build
>>the sched domains.
>>    
>>
>
>Maybe you could make that the default behavior?
>
>Jesse
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