10.4 vs. 8xMP: core affiinity issue workaround... Virtualization??

Discussion in 'Mac Pro' started by brooker, Apr 18, 2007.

  1. brooker macrumors regular

    Apr 4, 2007
    Ok, so the conclusion is that tiger can't make the Ocho run to full potential because it doesn't have a smart enough process scheduler...

    But what if you run some smart, multi-core aware linux install as a virtual machine, in Parallels or VMWare? Would that provide better access to all the cores?

    I don't know enough about the inner workings of operating systems, or the details of how Parallels/VMWare accesses the CPUs.

    Anyone have any experience running virtual servers on a multi-core Mac to speak to this?

    Anyone with an 8-way MP wanna try it out?
  2. NewbieNerd macrumors 6502a


    Sep 22, 2005
    Chicago, IL
    I may be wrong, but I think I read in the copy of Macworld magazine I just skimmed tonight in CVS that VMware is multicore aware, but not Parallels. I know on my Intel iMac and Macbook, it asks me if I want to use one core or two cores, but I have no idea if it will let you use all 4 or 8 cores on a Mac Pro.
  3. brooker thread starter macrumors regular

    Apr 4, 2007
    MC support in Parallels planned as well!

    Thanks for your post, that insight inspired some more research. I found this:

    So I think we might have a viable solution to the problem caused by Tiger's lameness and Leopard's slowness. Depending on what your usage needs are, of course... it looks like virtual machines will get all those cores spinning harmoniously, rather than leaving them to scramble and grab for cache data like ill-trained 2 year olds.

    Anyone with an 8-way MP installed VMWare yet? I'd love to see a screen shot that gives options for assigning up to 8 cores to a guest OS... Anyone tried it on a Quad?

    The next logical question is... What version of Linux does the best multi-core handling? If this all comes together, i might be able to convince my work that this is the server we need.
  4. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    Of all the OSes I know about Solaris handles this problem the best. The higher end Sun computrs have for many years been build with four CPUs and some RAM all on one card and then these cards are stuffed on tha buss to build the machines with 8, 16 or 64 CPUs. So Sun had some motivation to make sure CPU's mostly acceessed the RAM that was "local". Durring the boot process Solaris builds a model of the machine's hardware.

    Linux is not to bad either, not as sophisticated as Solaris but it does try to keep processes on the same processor.

    As for VMware, You'd have to first install Linux on the Mac Pro and use that as the host OS and then run VMware on linux and then load any other OS images inside a VM.

    Bottom line is if you want to run Mac OS X VMware will not help.

    Also I think we are running into a memory bandwidth issue with 8 cores. I think the 8 core MP is a vey specialized machine that very few people could justify. I fact I'd say it is pointless unless you run Activity Monitor on the quad core M and noic all four CPUs running at 100%. If one of then is only at 80% then adding even a 5th core will not help.
  5. brooker thread starter macrumors regular

    Apr 4, 2007

    Thanks for the feedback. Wow, Solaris sounds like a monster! What smart OS building!

    Are any versions of Linux any better with MC hardware than others?

    VMWare is developing a product for Mac, that is now in Beta 3, so i would not need to install Linux first.

    I'm considering running some servers on the MP that will need full access to processing power at frequent random times (as opposed to running a single big job regularly) -- so it seems to me that a virtual environment could isolate the necessary resources, no matter what else is happening on the computer.

    Technically speaking, according to your example, if you ever hit 400% on a Quad, you could benefit from a 5th core. But if i have ~8 heavy-duty apps open and running, and want to ensure that the virtual server has unrestricted access to a few cores (and plenty of RAM, of course) then having spare dedicated cores seems like it would be the way to go. Or i could get another machine. But why if it will work all in one tidy package?

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