Messages in this thread | | | Date | Wed, 24 Sep 2008 11:16:34 -0700 | From | "H. Peter Anvin" <> | Subject | Re: [PATCH 1/2] VMware guest detection for x86 and x86-64 |
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Cristi Magherusan wrote: > On Wed, 2008-09-24 at 22:23 +0800, Yan Li wrote: >> On Wed, Sep 24, 2008 at 05:10:24PM +0300, Cristi Magherusan wrote: >>> On Wed, 2008-09-24 at 20:22 +0800, Yan Li wrote: >>>> Detects whether we are running as a VMware guest or not. Detection is >>>> based upon DMI vendor string. >>>> >>>> It provides a function: >>>> int is_vmware_guest(void) >>>> that can be used easily to detect if we are running as a VMware guest >>>> or not. >>> We can also use this feature to force the HZ value to 100 or 250 at most >>> when running in a virtual environment, since VirtualBox had some issues >>> with this by taking a lot of CPU time when the HZ was set to 1000. >> That's good. But this function is used for detecting VMware guest >> only. Do you think VMware also suffers from this problem? >> > I don't know for sure about VMware, but someone who has it installed can > try it. I had this issue with a CentOS 5-server virtual machine > downloaded from http://www.thoughtpolice.co.uk/vmware/ > > The fix consisted in using a kernel compiled with the HZ value set to > 100 instead of the default which was 1000. >
HZ is a compile-time constant, though. Changing that would require adding a bunch of general divides, at the very least.
-hpa
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