[Freeswitch-users] VMWare voice quality

John Skopis (Lists) jlists at skopis.com
Thu Jan 22 17:27:42 PST 2009

Michael Collins wrote:
> If anyone figures this out please post it to this thread. I am working
> on a wiki page for the VMWare appliance and I would like to be able to
> inform people on how to handle this situation.

I had some issues under vmware fusion. They were resolved by adding
clock=pit [1] to the kernel boot params and switching to host-only
networking, and running natd + ipfw on the host system. The vmware natd
would probably also work. haven't tried myself. The clock=pit is the big
kicker. Also, recompiling the kernel with HZ=100 might help to reduce
the load on the host system. [2] Though, with a small number of
vms/vcpus on decent hw the number of context switches probably won't
have much of an effect.

[1] www.vmware.com/pdf/vmware_timekeeping.pdf
[2] http://communities.vmware.com/docs/DOC-3580

> Also, IIUC, those running VMWare Fusion on Macs are not experiencing
> this, correct? What about those using a hypervisor like ESXi? Any
> known issues?
> Thanks,
> MC
> On Thu, Jan 15, 2009 at 9:15 AM, Ken Rice <krice at suspicious.org> wrote:
>> On 1/15/09 11:01 AM, "Remko Kloosterman" <R.Kloosterman at mtel.nl> wrote:
>>> Hello Ken, hello all,
>>> I just read about the FreeSWITCH VMware applicance. I'm curious about
>>> your experiences with the audio quality on VMWare, so here's a new
>>> thread.
>>> I've installed freeswitch on VMware Server for Windows. The IVR audio
>>> always plays choppy, while the server itself has no performance issues.
>>> The same poor voice quality also goes for Asterisk or Yate, even on a
>>> very fast VMware ESX system.
>>> Did you experience the same and/or do you have pointers on how to
>>> troubleshoot and fix this?
>> There is a high resolution timer you need to enable on vmware... I'm not
>> familiar enuff with all the versions of vmware to advise there that switch
>> is, but they have a couple of articles on it in their knowledge base

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