[Freeswitch-users] Choppy audio when conferencing 4+ participants

[Colin Morelli]

Robert,

While I'd love to see VMs provide more stable ground for FS, it's simply
not the best task for a VM. Virtual machines scale well specifically
because you can overprovision them. It would not be nearly as
cost-effective to run VMs if each instance had a guaranteed dedicated slice
of hardware to operate on. While hypervisors are *very* good at task
prioritization, they're not perfect. If the hypervisor can't schedule
processor time when FS needs it because the CPU cores are momentarily taken
on other tasks, there's not a whole lot FS can do. This is not an issue
with just FS, but with all real-time applications. In most apps, even large
clock skews and bad hypervisors schedulers can go completely unnoticed. If
there's consistent 5-10ms every time you click to load a web page, you'd
probably have no idea. If there's 5-10ms jitter every time you try to read
20ms of audio, you have *really bad* audio. Granted most skews are not that
bad, but the effects are pronounced when you're dealing with data that's
real-time in nature.

Bilal,

I have no idea what AMI you're running, but a very rough "ear test" has
made me fairly confident that I can get better performance running
AmazonLinux AMIs over Ubuntu (and probably many others). It wouldn't
surprise me if AmazonLinux builds a custom kernel that has been tuned to
run better on AWS hardware. I'd say it's at least worth a quick experiment.

Best,
Colin

On Fri, Apr 14, 2017 at 4:34 PM, Mundkowsky, Robert <rmundkowsky at ets.org>
wrote:

> Michael
>
>
>
> Just curious, why so many problems with VMs?
>
>
>
> I would think most applications need real time clocks that provide
> consistent valid data?
>
>
>
> Bilal,
>
>
>
> you might try a larger AWS instance to make sure your are getting 100% of
> the box; might help some.
>
>
>
> Robert
>
>
>
> *From:* freeswitch-users-bounces at lists.freeswitch.org [mailto:
> freeswitch-users-bounces at lists.freeswitch.org] *On Behalf Of *Michael
> Jerris
> *Sent:* Friday, April 14, 2017 4:25 PM
> *To:* FreeSWITCH Users Help <freeswitch-users at lists.freeswitch.org>
> *Subject:* Re: [Freeswitch-users] Choppy audio when conferencing 4+
> participants
>
>
>
> can you reproduce the same issue on real hardware?  We’ve seen all kinds
> of weird timing issues that could account for this running on aws.
>
>
>
> On Apr 14, 2017, at 4:16 PM, Bilal Dar <bilal at rgate-systems.com> wrote:
>
>
>
> Its an AWS m3.2xlarge instance.
>
>
>
> On Fri, Apr 14, 2017 at 9:57 AM, Michael Jerris <mike at jerris.com> wrote:
>
> Real hardware or VM?
>
> > On Apr 14, 2017, at 12:48 PM, Bilal Dar <bilal at rgate-systems.com> wrote:
> >
> > I have been struggling with an issue for almost 2 weeks.
> >
> > Our regular calls have no quality issue and looking RTCP statistics
> network conditions are perfect. We have normally on peak hr 60 calls and
> around 10 conferences.
> >
> > We have noticed that when we have 2 conferences of 4 or 5 participants,
> audio starts breaking for the users who are on conference. Regular calls do
> not experience any quality degradation.
> >
> > I upgraded the server to specs of 30Gig memory and 8 vCPU but still the
> issue exists. Common thing I have noticed even during off-peak hrs is that
> two 4+ participant call can cause the issue.
> >
> > I have ruled out network & hardware. Last change I made was moved all
> users to G.711 from G.722. Now I am not sure what other steps I can take.
> Appreciate any suggestions.
>
>
>
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