Technical information

VMware, Inc. 25
Chapter 2 ESX and Virtual Machines
Large Memory Pages for Hypervisor and Guest Operating System
In addition to the usual 4KB memory pages, ESX also makes 2MB memory pages available (commonly
referred to as “large pages”). By default ESX assigns these 2MB machine memory pages to guest operating
systems that request them, giving the guest operating system the full advantage of using large pages. The use
of large pages results in reduced memory management overhead and can therefore increase hypervisor
performance.
If an operating system or application can benefit from large pages on a native system, that operating system
or application can potentially achieve a similar performance improvement on a virtual machine backed with
2MB machine memory pages. Consult the documentation for your operating system and application to
determine how to configure them each to use large memory pages.
More information about large page support can be found in the performance study entitled Large Page
Performance (available at http://www.vmware.com/resources/techresources/1039).
Hardware-Assisted MMU Virtualization
Hardware-assisted MMU virtualization is a technique that virtualizes the CPU’s memory management unit
(MMU). For a description of hardware-assisted MMU virtualization, see “Hardware-Assisted MMU
Virtualization (Intel EPT and AMD RVI)” on page 11; for information about configuring the way ESX uses
hardware-assisted MMU virtualization, see “Configuring ESX for Hardware-Assisted Virtualization” on
page 21.