Its in the Architecture

By Scott Ferguson  |  Posted 2008-09-23 Print this article Print


In addition, Intel spokespeople were talking about the virtualization capabilities found in the Nehalem architecture. These enhancements include a piece of technology called Extended Page Tables, which should help increase the performance around memory when it comes to creating virtual machines.

Intel's Extended Page Tables or EPT resemble a technology that AMD has been promoting with its quad-core Opteron processor called nested page tables or Rapid Virtualization Indexing.

In a regular hardware environment, the processor allows for virtual memory to map to the physical memory within a system.  

However, in virtual environments, the hypervisor-the piece of software that makes virtualization possible-creates another layer of virtual memory. What AMD's nested page tables and Intel's EPT allow for is the creation of a box around the hypervisor that allows the guest operating systems to nest within that space and lock the memory in place. This then makes switching between the guest operating systems much faster and the technology allows for better performance, while allowing virtual machines to move more quickly between different pieces of hardware.

Margaret Lewis, AMD's director of Commercial Software, told eWEEK that what AMD is trying to do with virtualization is to take some of the more complex tasks that had been performed in the software, such as memory allocation, and move those functions to the hardware. This type of chip design, Lewis said, eliminates some of the complexities, overhead and penalties associated with server virtualization and creating virtual environment.

"Memory handling is always expensive if you do it on a software level," Lewis said. "The more we can do with memory handling and switching between the different virtual machines and getting the memory set up so that each VM has its own space means that it makes it easier for software to run the application."

The next step then for AMD and Intel is I/O virtualization. When AMD launches a new server platform in 2009, the company is preparing to include a technology called IOMMU (I/O Memory Management Unit), which will allow for virtualization of the system's I/O traffic. At the same time, Intel with Nehalem will bring out a technology called VTD, which dedicates I/O resources for virtual machines. In this case, virtual I/O technology will allow the IT department to partition and assign I/O devices to virtual machines.

While at the VMworld show, Doug Fisher, vice president and general manager of Intel's Software Division, said customers are looking for not only how Intel can speed up virtualization through its chips, but what the company can offer through its chip sets and networking such as the ability to better allocate memory and I/O devices.

"The customer does not want to pick a platform based on one feature," Fisher said. "They look at what we are doing holistically and can we deliver the performance and reliability across the system to meet capabilities that they are looking for when they invest in a system."


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