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Why we need multiple levels of page tables?

    General discussion

  •  
    As we know, we use page table to transform virtual memory address to physical memory address, by this way, we can improve the efficiency of memory usage. When only populate the physical memory if needed.

    My question is: We have page table to solve that problem, why we need multiple levels of page tables?
     
    wiki said,  using multilevel page table, the top and bottom blocks of virtual memory tend to be the ones which are used most often and so efficiency can be improved by having separate page tables for these blocks.  But i want to know the details how the efficiency be improved?
     
     
    Tuesday, September 27, 2011 9:39 AM

All replies

  • As we know, we use page table to transform virtual memory address to physical memory address, by this way, we can improve the efficiency of memory usage. When only populate the physical memory if needed.
    This question does not seem to have anything to do with the Developer Preview of Windows 8.
     

    David Wilkinson | Visual C++ MVP
    Wednesday, September 28, 2011 9:40 AM
  • >This question does not seem to have anything to do with the Developer Preview of Windows 8.
     
    There's one commonality -- the version of Hyper-V on the client
    Windows 8 requires SLAT, that's a new requirement for Hyper-V. (SLAT
    == Second Level Address Translation)
     
     

    Bob Comer - Microsoft MVP Virtual Machine
    Wednesday, September 28, 2011 12:58 PM
  • This question does not seem to have anything to do with the Developer Preview of Windows 8.
    There's one commonality -- the version of Hyper-V on the client
    Windows 8 requires SLAT, that's a new requirement for Hyper-V. (SLAT
    == Second Level Address Translation)
    Ah, Hyper-V. Having Hyper-V is for me the greatest new non-Metro feature in Windows 8 , but one that I have not had a chance to try yet.
     
    But I'm hoping that it will allow me to wean myself off VMWare Server when I upgrade my Windows 7 HTPC to Windows 8.
     

    David Wilkinson | Visual C++ MVP
    Wednesday, September 28, 2011 3:27 PM
  • >Having Hyper-V is for me the greatest new non-Metro feature in Windows 8
     
    It'll have it's uses for 64-bit VM's and Hyper-V Server compatibility,
    but to tell the truth, I prefer Windows VPC + XP Mode for the seamless
    apps for what I use. (stupid legacy apps, what can I say, I need 'um)
    It's much harder to do with Hyper-V.
     
    As for you're VMWare, I remember your usage and if you're hardware
    supports SLAT + VTx, I think you'll really really like Hyper-V on the
    client side.
     
     

    Bob Comer - Microsoft MVP Virtual Machine
    Wednesday, September 28, 2011 3:52 PM
  • As for you're VMWare, I remember your usage and if you're hardware
    supports SLAT + VTx, I think you'll really really like Hyper-V on the
    client side.
    Hmmm, I have two similar AMD machines:
     
    1. Socket AM3, Athlon II X4, 8GB DDR3 (HTPC, built March 2010)
     
    2. Socket AM3+, Athlon II X4, 8GB DDR3 (Workstation, built April 2011)
     
    Will these work with Hyper-V? The older one works fine with VMWare server under Windows 7. I like a server virtualization solution because it automatically shuts down and restarts the VM's. But the interface of VMWare Server is kind of klunky.
     

    David Wilkinson | Visual C++ MVP
    Thursday, September 29, 2011 12:27 AM
  •  
    >Will these work with Hyper-V?
     
    I don't know for sure, but I think you're good, but it may depend on
    the specific processors.  Here's a list I found:
     
     
    I have a Phenom II x6 at home that runs it well...
     
     

    Bob Comer - Microsoft MVP Virtual Machine
    Thursday, September 29, 2011 1:34 PM
  • Will these work with Hyper-V?
    I don't know for sure, but I think you're good, but it may depend on
    the specific processors. Here's a list I found:
     
    <http://support.amd.com/us/kbarticles/Pages/GPU120AMDRVICPUsHyperVWin8.aspx>
    Thanks, Bob. My machines are Athlon II x4 (Propus) so I think it should work.
     
    Just a matter of finding some time to try it...
     

    David Wilkinson | Visual C++ MVP
    Friday, September 30, 2011 10:37 AM
  • >Thanks, Bob.
     
    You're welcome.
     
    You turn it on via Windows Features...
     
     

    Bob Comer - Microsoft MVP Virtual Machine
    Friday, September 30, 2011 1:05 PM