[App_rpt-users] First experience with ACID app_rpt & usbradio audio popping problem.

David McGough kb4fxc at inttek.net
Wed Nov 18 10:55:36 EST 2009

> All the machines you have tried except one are sub 1GHz. And the 1.1GHz machine you were using is a Duron processor
> which is the low end of the low end! In our documentation we specify a machine with a clock speed of 1GHz or better. The
> DSP routines in chan_usbradio/XPMR may be getting bogged down for an instant during the fork or ethernet packet
> transmission of the statpost info. We have not had much luck running ACID on machines under 1GHz and we have not tested
> it on Celeron or Duron processors.
> There are lots of users out there using ACID, but I suspect if you ask them, they are running processors north of 1GHz
> and that most of them are running later vintage processors from Intel and AMD.
> If you want to continue using old motherboards with slower clock speeds and old low end processors, then you have to
> expect these kinds of issues.
> Steve

Hi Steve,

I have choppiness problems, too, as I've mentioned in threads in the past.  
I hacked chan_usbaudio.c slightly -and- turned OFF RADIO_RELAX and have
radically improved results--almost no chop at all...I haven't encountered
the statpost issue since I'm not sending out updates yet. I also had
ugly timer issues with my fastest box. Going to a kernel and the
hi-res timer and patching zaptel/kernel/ztdummy.c fixed this.

I'm running recent boxes--one is a Athlon64X2 4400+, a second is an A64X2
6000+. They're both MSI motherboards. One is ATI chipset, the other is
NVIDIA. I've also used slower (Single core 32bit Athlon 2800+, VIA
chipset) machines in the past with the same exact problems. And, all the
boards have different network adapters. I'm even running 3ware RAID 1 on
one of the boxes. ...Note also that I'm running MANY of these boxes (well
over 100!) in production using linux at my company--several even running
the asterisk PBX software...Never any problems at all.

Also, if I use various linux utilities to read/write the CM108 audio
device directly, I've not had any dropped/chopped audio. I realize this is
a different scenario from how audio is handled by asterisk, but, it leads
me to believe that there isn't any systemic problem with my
linux/hardware/USB config.

Thanks in advance!

73, David kb4fxc

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