On 04/20/2011 05:01 PM, Benjamin Herrenschmidt wrote: > On Wed, 2011-04-20 at 12:07 +0200, Peter Zijlstra wrote: >> On Thu, 2011-03-10 at 15:10 +0100, Peter Zijlstra wrote: >>> >>> Also, still waiting to hear from the Power7 folks on how often >>> they think to rebuild the topology and how they think that makes >>> sense, afaict Power7 does have actual NUMA nodes unlike s390, so >>> I'm still not seeing how that's going to work properly at all. >> >> Jesse care to answer? I hear from Ben you're responsible for that >> mess. > > "responsible for this mess" is a big word :-) > > But he's the one to last play with that code ... Jesse ? >
Hi Peter! According the the Power firmware folks, updating the home node of a virtual cpu happens rather infrequently. The VPHN code currently checks for topology updates every 60 seconds, but we can poll less frequently if it helps. I chose 60 second intervals simply because that's how often they check the topology on s390. ;-) As for updating the memory topology, there are cases where changing the home node of a virtual cpu doesn't affect the memory topology. If it does, there is a separate notification system for memory topology updates that is independent from the cpu updates. I plan to start working on a patch set to enable memory topology updates in the kernel in the coming weeks, but I wanted to get the cpu patches out on the list so we could start having these debates. :) Sincerely, Jesse Larrew Software Engineer, Linux on Power Kernel Team IBM Linux Technology Center Phone: (512) 973-2052 (T/L: 363-2052) jlar...@linux.vnet.ibm.com
_______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
