On Thu, Jul 25, 2013 at 03:52:49PM -0500, Tim Nelson wrote: > Greetings- > > I'm running some USB DAHDI hardware on a system with a tickless > kernel. The audio quality is quite poor. Could the tickless kernel > be to blame? If so, when recompiling a kernel that is *not* > tickless, is there a recommended KERNEL_HZ value? IIRC, older > kernels used to be 1000, but newer ones are 250.
I doubt it's the tickless kernel that is causing your issue. Normally if you have DAHDI hardware, then it should be generating interrupts which drive the mixing / passing of audio. There shouldn't be any reliance on the system timer tick. Also, for most Asterisk installations that are using the system timer for mixing I've not seen any problems with 250 HZ. Most VOIP systems mix audio at in at least 20ms size packets, so even at 250 HZ there are 5 timer expirations for each audio packet. Keeping the kernel tickless should also work fine here when using a software timer to mix your audio since the kernel will set the timer to fire at the next timer expiration (whatever that was set to). So, in summary...I've not seen any problems related to the tickless kernel. -- Shaun Ruffell Digium, Inc. | Linux Kernel Developer 445 Jan Davis Drive NW - Huntsville, AL 35806 - USA Check us out at: www.digium.com & www.asterisk.org -- _____________________________________________________________________ -- Bandwidth and Colocation Provided by http://www.api-digital.com -- New to Asterisk? Join us for a live introductory webinar every Thurs: http://www.asterisk.org/hello asterisk-users mailing list To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
