[asterisk-dev] MFC/R2 Asterisk Channel Driver

[Luis Antonio Prata Barbosa]

>
>
> For something like G.729 encode/decode a direct comparison between a
> processor on a card and host processing comes down to a 1:1 comparison
> of their processing performance (not their MIPS - a customised DSP
> processor's instructions typically do the work of several general
> purpose processor instructions, and quality of match between the working
> set and the cache size has a huge (10-20 fold) impact on speed on a
> Pentium class processor). Echo cancellation is a special case. The
> adaption process in an echo cancellor is a control loop, and it gets
> bogged down in latency issues when run on the host processor. To keep
> the signal latency low means loosing most of the benefits of PCI bus
> mastering (those nasty 1ms chunks that many cards work in), and
> suffering enormous context switching overheads.


That`s my point... using an exclusive core as data handler, and running only
this task to minimize context switching, we could take care of 8x faster
interrupts didn`t we ?

PCI overhead will increase, but I don`t think it would be a problem. We are
talking about 120 channels * 64kbits/s (8kbytes/s) =  960kbytes/sec ...

Well, let me study a little bit more about the subject.... may be I need not
a symetrical (SMP) multiprocessor support but something assymetrical...

Luis A P Barbosa
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