From mboxrd@z Thu Jan 1 00:00:00 1970 From: ankita@in.ibm.com (Ankita Garg) Date: Fri, 10 Jun 2011 23:03:45 +0530 Subject: [PATCH 00/10] mm: Linux VM Infrastructure to support Memory Power Management In-Reply-To: <20110610171939.GE2230@linux.vnet.ibm.com> References: <1306499498-14263-1-git-send-email-ankita@in.ibm.com> <20110528005640.9076c0b1.akpm@linux-foundation.org> <20110609185259.GA29287@linux.vnet.ibm.com> <20110610151121.GA2230@linux.vnet.ibm.com> <20110610155954.GA25774@srcf.ucam.org> <20110610165529.GC2230@linux.vnet.ibm.com> <20110610170535.GC25774@srcf.ucam.org> <20110610171939.GE2230@linux.vnet.ibm.com> Message-ID: <20110610173345.GA8434@in.ibm.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org 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 at in.ibm.com) Linux Technology Center IBM India Systems & Technology Labs, Bangalore, India