Sun Microsystems VERSION 3.1.0_BETA2 Linux and X11 guests, Linux guests may cause a high CPU load

11Troubleshooting

11.3Linux and X11 guests

11.3.1 Linux guests may cause a high CPU load

Some Linux guests may cause a high CPU load even if the guest system appears to be idle. This can be caused by a high timer frequency of the guest kernel. Some Linux distributions, for example Fedora, ship a Linux kernel configured for a timer frequency of 1000Hz. We recommend to recompile the guest kernel and to select a timer frequency of 100Hz.

11.3.2 AMD Barcelona CPUs

Most Linux-based guests will fail with AMD Phenoms or Barcelona-level Opterons due to a bug in the Linux kernel. Enable the I/O-APIC to work around the problem (see chapter 3.3.2, “Advanced” tab, page 46).

11.3.3 Buggy Linux 2.6 kernel versions

The following bugs in Linux kernels prevent them from executing correctly in VirtualBox, causing VM boot crashes:

•The Linux kernel version 2.6.18 (and some 2.6.17 versions) introduced a race condition that can cause boot crashes in VirtualBox. Please use a kernel version 2.6.19 or later.

•With hardware virtualization and the I/O APIC enabled, kernels before 2.6.24- rc6 may panic on boot with the following message:

Kernel panic - not syncing: IO-APIC + timer doesn’t work! Boot with apic=debug and send a report. Then try booting with the ’noapic’ option

If you see this message, either disable hardware virtualization or the I/O APIC (see chapter 3.4, System settings, page 47), or upgrade the guest to a newer kernel.2

11.3.4Shared clipboard, auto-resizing and seamless desktop in X11 guests

Guest desktop services in guests running the X11 window system (Solaris, Linux and others) are provided by a guest service called VBoxClient, which runs under the ID of the user who started the desktop session and is automatically started using the following command lines

2See http://www.mail-archive.com/git-commits-head@vger.kernel.org/msg30813. html for details about the kernel fix.

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