On Fri, Jun 10, 2011 at 10:19:39AM -0700, Paul E. McKenney wrote: > On Fri, Jun 10, 2011 at 06:05:35PM +0100, Matthew Garrett wrote: > > On Fri, Jun 10, 2011 at 09:55:29AM -0700, Paul E. McKenney wrote: > > > On Fri, Jun 10, 2011 at 04:59:54PM +0100, Matthew Garrett wrote: > > > > For the server case, the low hanging fruit would seem to be > > > > finer-grained self-refresh. At best we seem to be able to do that on a > > > > per-CPU socket basis right now. The difference between active and > > > > self-refresh would seem to be much larger than the difference between > > > > self-refresh and powered down. > > > > > > By "finer-grained self-refresh" you mean turning off refresh for banks > > > of memory that are not being used, right? If so, this is supported by > > > the memory-regions support provided, at least assuming that the regions > > > can be aligned with the self-refresh boundaries. > > > > I mean at the hardware level. As far as I know, the best we can do at > > the moment is to put an entire node into self refresh when the CPU hits > > package C6. > > But this depends on the type of system and CPU family, right? If you > can say, which hardware are you thinking of? (I am thinking of ARM.) > And also whether the memory controller is on-chip or off-chip ? As package could be in C6, but other packages could be refering memory connected to this socket right ? And as Paul mentioned, at this point the ARM SoCs that have support for memory power management, have only a single node. -- Regards, Ankita Garg (ankita@xxxxxxxxxx) Linux Technology Center IBM India Systems & Technology Labs, Bangalore, India -- 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 internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>