[asterisk-users] Audio cutting in and out - asterisk 13.1 cert6 / confbridge

Joshua Colp jcolp at digium.com
Thu Jun 30 08:45:18 CDT 2016

Robert McGilvray wrote:
> Thanks Joshua. We're talking about pretty long gaps in the audio,
> probably around 10-15 seconds which is quite a bit of missed ticks at
> 20ms sampling. I was poking around the timing code trying to get a
> better understanding of things and found that Asterisk uses
> timerfd_create with CLOCK_MONOTONIC as the clock. The man page states
> CLOCK_MONOTONIC is affected by incremental adjustments to the time
> made by things like NTP.
> I may be completely off track here but would something like vmtools
> that tries to correct the clock skew (caused by VMware) be causing
> some issues here? Meaning that if asterisk calls timerfd_create but
> then the time is adjusted could that throw off the timing of the
> descriptor?

I'm not familiar with the inner workings of timerfd so I don't really 
know, but it is certainly possible. It's also possible that the sheer 
I/O is causing timing to get thrown off in the environment.

Joshua Colp
Digium, Inc. | Senior Software Developer
445 Jan Davis Drive NW - Huntsville, AL 35806 - US
Check us out at: www.digium.com & www.asterisk.org

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