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We've been doing graphics rendering using Maxwell Render on a Ubuntu box with a 6 core AMD Phenom II Processor. Ubuntu handles all 6 cores brilliantly, but a 4 core laptop is almost as fast. We'd like to upgrade and create a 64 core rackmount using:

1X TYAN S8812 Motherboard (four processor sockets) 4X AMD Opteron 6200 (Interlagos) 16 core Processors

Can anyone confirm or deny (with documentation, not opinion) whether Ubuntu (or Ubuntu Server) out of the box will recognize and handle all 64 cores? (e.g. is there an upper limit to how many cores Ubuntu can handle out-of-the-box?)

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  • 1. Thats a huge machine. 2. I don't think you're in the right place, I think you might want serverfault, but I'll leave that up in the air.
    – jrg
    Jan 17, 2012 at 18:24
  • I think this is perfect for Ask Ubuntu; however, I can only offer an opinion of "Yes this will work" The furthest I've taken Ubuntu is 32 cores. Jan 17, 2012 at 18:44

1 Answer 1

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Basically, this comes down to "can the Linux kernel handle this many cores". The actual number of cores supported is defined by a numerical option that can be set at kernel compile time. The kernel configuration shipped by Ubuntu can be seen here, and in that file, we find

CONFIG_NR_CPUS=256

so 64 should work fine. Actually, there are systems with that many (and more) cores active; as an especially impressive example, see this screenshot of htop running on a 128 core machine.

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  • Thank you all for the quick responses. Awesome! I'd welcome additional evidence to support the conclusion, but jstarek's answer, explanation and screenshot is VERY promising. Marco's experience with 32 cores is quite encouraging as well. Will post if/when we manage to execute. Thanks all!
    – Gene
    Jan 17, 2012 at 22:21
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    Gene, how did your tests work out so far?
    – jstarek
    Mar 6, 2012 at 10:25

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