From: King, Ed (EKing@mail.HamiltonTN.gov)
Date: Thu Feb 10 2005 - 15:42:22 EST
Thanks to all the folk who responded to my questions!
>Question 1:
>If we install a secondary 5/250 cpu into the Alpha, will Tru64 4.0g
>recognize and use the second cpu automatically, or do we need to tell the
>kernel about the 2nd cpu? Do we tell the kernel about the new cpu before,
>during, or after the install of the cpu?
Responses:
You can install the 2nd cpu and the SRM will immediately recognize it. The
kernel will also use it without any reconfiguration needed.
--- I think you need an SMP license for the OS to use both CPUs. --- In relation to the first question, as far as I remember an extra license is required to run more than 1 CPU - an SMP license. --- You should be able to just shutdown, install the additional CPU, and boot. There is nothing else required. --- You need to register the appropriate license PAK to enable the second CPU. The license PAK paperwork should come with the CPU. There isn't anything else you need to do, the kernel is already prepared to have multiple CPUs in that system type. --- Yes and no... As in, yes, you have to do something (add the CPU license to the system) but no commands required beyond adding the license (no need to re-build the kernel or anything. --- This depends. To utilize more than one CPU, you need a special license. If you already have that installed, then you are good to go, no kernel rebuild necessary to add CPUS or memory. There may be some kernel params that could be adjusted afterwards. --- You will need a license for the second CPU and then it should be seen by Tru64 without any intervention on your part. In addition, the two CPU share all the memory, they do not each get a board. Note however that there may be dip switches on the CPU that have to be sweat so get the installation instruction if you can. --- The confusion about adding cpus may have come from the 2000/200a and 2100/2100a upgrades. It was possible to upgrade the mainboard on the original models to the faster PCI bus versions. It was a multi-step process requiring a special kernel build prior to the upgrade in order to recognize the new model of cpu. This is /not/ necessary when simply adding another cpu that matches the existing one. --- Yes, it will use it automatically. You will need to go into LMF and enter the license key information. Afterwards, issue a "reset" command to resynchronize the updated license information with the kernel. 2. Oracle will use the CPUs automatically. 3. The memory is shared. --- You need to load an additional OSF_BASE license to enable the CPU no kernel build , you should register the license before adding the cpu. --- When I added the 2nd CPU I had to make sure that both were the same. I forgot exactly what I was looking for but both of the processors must have a flag that matches. When the system is down you can type in show cpu from the >>> Prompt You must have 2 Power Supplies if you are running 2 CPU's Each CPU requires it's own liscense also. (I can look up what these cost but I think the 2nd CPU comes with liscense.) After physically installing the hardware. I went in an did a show fru and show cpu from >>> Booted into single mode did a sizer command to build a temp config file for the Kernel compared the temp file and the original one doconfig command to rebuild the kernel copied the new kernel to the original location after copying the original to a safe place Synced the system then rebooted > Question 2: > Will Oracle 7.3 automatically "load balance" between both cpus? Or is > there some sort of load balancing command that I need to use when I > start Oracle? Responses: Oracle is a multi-threaded application and the threads will be distributed by the OS scheduler to run across all available (licensed) CPUs. --- Process scheduling is on all cpu's by default. Extra tricks like runon, processor sets or class sheduling are required to bind a process to a cpu. --- We have been running Oracle on multiple CPU's for a number of years and the load appears to be equally distributed (but oracle is not my job so I don't know the details). --- The SMP (symmetric multi-processing) features of the OS will take advantage of the 2nd cpu automatically, however, applications that are compiled in a single-threaded model may only run on one cpu at a time. If there are multiple applications executing simultaneously (normal there are, of course) both cpus will be used but processes will not migrate from cpu to cpu to balance the load between them. > Question 3: > If an Alpha2000 has 2 cpus and 2 memory boards, does one cpu use one memory > board exclusively, and the other cpu uses the other memory board > exclusively, or do they share the memory? Responses: The AS2X00 is a bus-based architecture where all CPUs share the memory (compete for). --- The memory is fully shared between the cpus. If the memory modules match in size and configuration data access is interleaved across the modules. The technical reference is available here : http://ftp.digital.com/pub/Digital/Alpha/systems/as2100/docs/technical_summa ry.pdf The rest of the available docs are here : http://h18002.www1.hp.com/alphaserver/archive/2000/2000_tech.html --- No, all the memory is in a single pool, and it's shared by all the uses of memory. There are more modern system designs where that's not strictly true, but your older system is "pure SMP", there is no logic to divvy up the memory among the CPUs based on which boards or whatever contain it, all the memory is just one big area that's managed as a homogeneous pool. --- Oracle should be SMP safe. As long as there are multiple processes (or more accurately threads) ready to run, the kernel scheduler will keep both CPUs busy (when there are two CPUs; if there are more, it tries to keep them ALL busy). To the extent that Oracle may prevent certain parallelism to provide correct database transaction semantics, you may not be able to keep all the CPUs busy all the time, but that is all that's really involved.
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