[Adding linux-mm where this should have been in the first place] On Mon, Nov 15, 2010 at 08:13:14AM -0600, Christoph Lameter wrote: > On Sun, 14 Nov 2010, KOSAKI Motohiro wrote: > > > Nice! > > Lets not get overenthused. There has been no conclusive proof that the > overhead introduced by automatic migration schemes is consistently less > than the benefit obtained by moving the data. Quite to the contrary. We > have over a decades worth of research and attempts on this issue and there > was no general improvement to be had that way. I agree it's not a good idea to enable this by default because the cost of doing it wrong is too severe. But I suspect it's a good idea to have optionally available for various workloads. Good candidates so far: - Virtualization with KVM (I think it's very promising for that) Basically this allows to keep guests local on nodes with their own NUMA policy without having to statically bind them. - Some HPC workloads. There were various older reports that it helped there. So basically I think automatic migration would be good to have as another option to enable in numactl. -Andi -- ak@xxxxxxxxxxxxxxx -- Speaking for myself only. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>