Messages in this thread | | | Date | Fri, 14 Apr 2006 11:17:16 +1000 | From | Peter Williams <> | Subject | Re: smpnice: issues with finding busiest queue |
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Siddha, Suresh B wrote: > On Thu, Apr 13, 2006 at 10:05:51AM +1000, Peter Williams wrote: >> There be dragons here :-(. >> > > At more places in this part of the world (smpnice) :) > > We need to relook at find_busiest_queue()... With the current weighted > calculations, it doesn't always make sense to look at the highest weighted > runqueue in the busy group.. > > for example on a DP with HT system, how does the load balance behave with > Package-0 containing one high priority and one low priority, Package-1 > containing one low priority(with other thread being idle).. > > Package-1 thinks that it need to take the low priority thread from Package-0. > And find_busiest_queue() returns the cpu thread with highest priority task.. > And ultimately(with help of active load balance) we move high priority > task to Package-1. And same continues with Package-0 now, moving high priority > task from package-1 to package-0.. > > Even without the presence of active load balance, load balance will fail > to balance(having two low priority tasks on one package, and high > priority task on another package) the above scenario.... > > We probably need to use imbalance(and more factors) to determine the busiest > queue in the group.....
A patch would be nice.
-- Peter Williams pwil3058@bigpond.net.au
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