*Non-Uniform Memory Access* (*NUMA*) is a computer memory design used in multiprocessing , where the memory access time depends on the memory location relative to a processor. Under NUMA, a processor can access its own local memory faster than non-local memory (memory local to another processor or memory shared between processors). So it is not about giving a process its own memory so much as taking a processor with its own memory and allowing it to share. in a manner that is efficient the wiki on it is really good. http://en.wikipedia.org/wiki/Non-Uniform_Memory_Access my experience with NUMA was if it was disabled you had a huge performance hit with an exception for multiple single threaded tasks as opposed to multiple threaded tasks that may use multiple cores/processors and access a shared pool. NUMA is only relevant when you are dealing with multiple processors really as single processors even with a large number of cores use the same interconnect to memory. On Mon, Jun 3, 2013 at 1:27 PM, Nadim Hoque wrote: > If i recall AMD started doing NUMA which each core gets a dedicated amount > of memory that is tied to it. The plus side is that when the core needs > something in its own memory region it does not need to put the request in > the queue like in non-numa and gets it faster. The down side is if it needs > data in a memory region that belongs to another core it will take longer > since it essentially has to ask that core for that data. In non-numa > architecture the entire memory space is allocated to all cores which means > that each core can access memory with out asking another for data. The > problem with this is that all memory requests is put in a queue and the > core has to wait until the memory controller is able to process the > request. For many core and lot of memory systems you are mostly better off > with NUMA. Correct me if I am wrong though. > > > On Mon, Jun 3, 2013 at 7:25 AM, Stephen wrote: > >> Not really, Dual channel mode means you can read and write to both Banks >> of memory at the same time (aka Ganged). Single Channel means you treat all >> ram as a single bank reading and writing to one and then the other. think >> Raid 0 vs JBOD if that helps. >> >> I personally have had 0 issue with greater than 4 GB of ram in a machine >> with Linux and a 64 bit kernel. and i have worked with multiple >> distributions over the years back and forth. >> >> the main difference between Intel and AMD i have seen since the core i >> series CPUs were released is that AMD still has wicked fast memory >> performance but Intel wins most everything else. >> >> If you have multiple processors you will want to look for numa. This >> allows inter processor communication for ram access. >> >> It should not matter if you are running ganged or unchanged your is >> should see all ram installed with the exception of the PCI/pcie/chip set >> nibbling 100 to 700mb for doing its thing in consumer chipsets. >> On Mon, Jun 3, 2013 at 6:36 AM, keith smith wrote: >> >>> >>> I found this in an on-line discussion: >>> >>> Ganged = dual channel mode for ram. All cores get access to 100% of the >>> ram. >>> >>> unganged = single channel. Each core gets access to a stick of ram. >>> >>> Is this correct? >>> >>> >>> ------------------------ >>> Keith Smith >>> >>> --- On *Mon, 6/3/13, Nathan England * wrote: >>> >>> >>> From: Nathan England >>> Subject: Re: AMD vs Intel memory managemement >>> To: "Main PLUG discussion list" >>> Date: Monday, June 3, 2013, 1:35 AM >>> >>> >>> >>> >>> >>> >>> Yeah, it's a wonderful thing AMD calls "unganged" mode. I have 8 GB of >>> ram in my server and the motherboard has enabled "unganged" mode to be more >>> efficient. CentOS only recognizes 5.8 GB of ram and I cannot turn off >>> unganged mode. >>> >>> >>> >>> I love it... >>> >>> >>> >>> >>> >>> >>> >>> >>> On Sunday, June 02, 2013 17:46:19 keith smith wrote: >>> >>> >>> >>> >>> Hi, >>> >>> After that great thread on 32bit vs 64bit, I was wondering if it would >>> be beneficial at this point to drill down to the CPU level : AMD vs Intel. >>> >>> We had a great thread a while ago the AMD CPU, however I do not think >>> that thread covered memory management. >>> >>> I almost went for an AMD CPU this go around (I have a couple from prior >>> purchases), however after hearing that AMD does some weird memory >>> management at the core level, assigning memory by the bank to each core, I >>> thought I would go with an Intel CPU. >>> >>> If I understand this correctly, It sounds like under some or most >>> circumstances the server will lose a portion of the total memory because >>> under AMD RAM is assigned at the core level and bank level. I assume Intel >>> uses memory as a pool. Need memory just grab some until it is gone. >>> >>> Any thoughts on this? >>> >>> Thanks! >>> >>> ------------------------ >>> Keith Smith >>> >>> >>> >>> -- >>> >>> >>> >>> >>> >>> >>> >>> Regards, >>> >>> >>> >>> Nathan England >>> >>> >>> >>> ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ >>> >>> NME Computer Services http://www.nmecs.com >>> >>> Nathan England (nathan@nmecs.com) >>> >>> Systems Administration / Web Application Development >>> >>> Information Security Consulting >>> >>> (480) 559.9681 >>> >>> >>> >>> -----Inline Attachment Follows----- >>> >>> --------------------------------------------------- >>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>> To subscribe, unsubscribe, or to change your mail settings: >>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>> >>> >>> --------------------------------------------------- >>> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >>> To subscribe, unsubscribe, or to change your mail settings: >>> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >>> >> >> >> >> -- >> A mouse trap, placed on top of your alarm clock, will prevent you from >> rolling over and going back to sleep after you hit the snooze button. >> >> Stephen >> --------------------------------------------------- >> PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org >> To subscribe, unsubscribe, or to change your mail settings: >> http://lists.phxlinux.org/mailman/listinfo/plug-discuss >> > > > > -- > Nadim Hoque > Systems Support Analyst > Engineering Technical Services > Arizona State University > Cell: 480-518-6235 > > --------------------------------------------------- > PLUG-discuss mailing list - PLUG-discuss@lists.phxlinux.org > To subscribe, unsubscribe, or to change your mail settings: > http://lists.phxlinux.org/mailman/listinfo/plug-discuss > -- A mouse trap, placed on top of your alarm clock, will prevent you from rolling over and going back to sleep after you hit the snooze button. Stephen