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Improving performance for a Linux host operating system

There are two suggestions for improving performance on a Linux host operating system:

This topic also includes information about how to use more than 1GB of memory on a Linux host operating system.

Use full-screen mode

Full-screen mode is faster than window mode. As a result, if you do not need to have your virtual machine and your host sharing the screen, try switching to full-screen mode.

The extreme case of this is VGA mode. VGA mode is any mode where the screen is in text mode (such as with DOS or Linux virtual terminals), or 16-color 640 x 480 graphics mode (such as with the Windows 9x clouds boot screen or any guest operating system that is running without the SVGA driver provided by VMware Tools).

On a Linux host, full-screen VGA mode uses the underlying video card directly, so graphics performance is effectively very close to that of the host. By contrast, window mode VGA is more expensive to emulate than window mode SVGA. As a result, if you will be running for an extended period of time in VGA mode (for example, if you are installing an operating system using a graphical installer) you should see a very significant performance boost if you run in full-screen mode.

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Disconnect the system timer

Certain guests (such as Windows 98) expect a very high interrupt rate from their system timers. Workstation on a Linux host operating system uses /dev/rtc, the real-time clock device, to try to keep up. However, continually servicing /dev/rtc and using it to maintain a high interrupt rate increases the load on the host, even when the virtual machine does not appear to be busy.

To try running without /dev/rtc, disconnect it using the "Devices" menu. This may not make a critical difference in performance, but it can help reduce the load on the host.

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How to use more than 1GB of memory on a Linux host operating system

By default, Linux kernels in the 2.2.x series support 1GB of physical memory. If you want to use more memory in Linux, you can take one of several approaches.

The "CONFIG_2GB" option calls for recompiling your kernel as a 2GB kernel. You do this by recompiling your kernel with "CONFIG_2GB" enabled. This allows Linux to support nearly 2GB of physical memory by dividing the address space into a 2GB user chunk and 2GB kernel chunk (as opposed to the normal 3GB User, 1GB kernel).

The third approach uses the "CONFIG_BIGMEM" option in Linux. With the "CONFIG_BIGMEM" option enabled, the kernel does not directly address all of physical memory and it can then map 1GB (or 2GB) of physical memory into the address space at a time. This allows the use of all of physical memory at the cost of changing the semantics the kernel uses to map virtual to physical addresses. However, VMware products expect physical memory to be mapped directly in the kernel's address space and thus do not work properly with the "CONFIG_BIGMEM" option enabled.

Workarounds

If you are using a 1GB kernel with "CONFIG_BIGMEM" enabled and have 960MB to 1983MB of memory, Workstation will not run. To work around this issue, you can either:

If you have a 1GB kernel with "CONFIG_BIGMEM" enabled and have more than 1983MB of memory, you can do one of the following:

If you are using a 2GB kernel with "CONFIG_BIGMEM" enabled and have 1984MB or more memory, Workstation will not run. You can either pass the boot-time switch "mem=1983M" at the LILO prompt or add it to lilo.conf to disable "CONFIG_BIGMEM" and thus allow you to run Workstation. To use the switch:

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