[asterisk-users] Linux Kernel Timer Frequency and Asterisk

[Tzafrir Cohen]

On Thu, Feb 08, 2007 at 02:15:15AM +0100, Patrick wrote:
> On Wed, 2007-02-07 at 14:53 -1000, Mark Coccimiglio wrote:
> > Ok here is a real geek question,
> > 
> > I building my own linux kernel for my asterisk system and came across 
> > the kernel setting for the timer frequency.  I have one of 3 hardcode 
> > choices 100Hz, 250 Hz and 1000Hz.  From what I understand the default 
> > Freq was changed from 100Hz in kernel 2.4 to 1000Hz (1KHz) in kernel 
> > 2.6.  Timing is a BIG issue in asterisk with all the TDM and zap channel 
> > stuff.  My guess is to go with the lower 100 or 250 Hz option but that 
> > is only a guess.  The 1KHz sounds like it will conflict with the Zap 
> > 1khz timer (or am I wrong about that).  Does anyone know what the 
> > prefered settings are for Trixbox or AsteriskNOW (or the asterisk code 
> > forks e.g. OpenPBX)?  Please let me know what your experience has been.
> 
> Trixbox is based on CentOS4 which uses 1000Hz. Iirc the same goes for
> FC6 with a recent kernel and the upcoming Fedora 7.

Trixbox is based on RHEL, that uses kernel 2.6.9. The frequency speed is
configurable as of 2.6.13 .

Distributions tend to stick with the default of 250Hz, but this is not
necessarily ideal for Asterisk.

BTW: The default kernel of Debian Etch is non-preemptable, which is
centainly not a good idea for Asterisk.

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               Tzafrir Cohen       
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