[asterisk-users] Codec and CPU load

[Gordon Henderson]

On Tue, 26 Aug 2008, aymen warfalli wrote:

>
> Hi
>
> as maximum link capacity could be calculated using codecs and channel 
> types so , regarding the CPU and processors load , Is there any formula 
> or (any relations could help ) that can give the maximum CPU load 
> (mainly processor and RAM ) or scalability average using asterisk 
> channels , codecs , applications ?.

The easy answer to this is: No.

Far too many variables. Not just cpu speed, but cpu cache size, memory 
type & speed, external interfaces (over a PCI bus/TDM or Ethernet/SIP/IAX) 
other tasks the CPU might be doing, compile-time optimisations, kernel 
optimisations, etc.

As a generalisation, without transcoding you'll be able to manage 100's of 
calls on a modern Intel or AMD server platform, but all bets are off when 
you turn on transcoding, echo cancellation, etc.

Gordon