> As Andi mentioned, the wakeup latency is not expected to be noticeable. And > these power-savings logic is turned on in the hardware by default. So its not > as if this patchset is going to _introduce_ that latency. This patchset only > tries to make the Linux MM _cooperate_ with the (already existing) hardware > power-savings logic and thereby get much better memory power-savings benefits > out of it. You will still get the blame :-) By grouping active memory areas along h/w power boundaries you enable the power saving modes to kick in (where before they didn't because of scattered access to all areas). This seems very similar to scheduler changes that allow processors to go idle long enough to enter deep C-states ... upsetting users who notice the exit latency. The interleave problem mentioned elsewhere in this thread is possibly a big problem. High core counts mean that memory bandwidth can be the bottleneck for several workloads. Dropping, or reducing, the degree of interleaving will seriously impact bandwidth (unless your applications are spread out "just right"). -Tony -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href