[Asterisk-Users] RAID affecting X100P performance...

[Steven Critchfield]

On Fri, 2004-07-30 at 18:55, Andrew Kohlsmith wrote:
> On Friday 30 July 2004 19:51, Mike Benoit wrote:
> > Tuning these [PCI latencies] should allow you to give your TDM cards
> > long burst lengths, and make your IDE devices very premptable...
> 
> I would have figured you want very short burst lengths to prevent any one 
> device from hogging the PCI bus and delaying your VOIP data. IIRC the VOIP 
> traffic is very short anyway (1000 interrupts a second, 8 bit PCM data or 64 
> bytes of actual VOIP data (sampled at 8000Hz, that's 8 8 bit samples every 
> interrupt) each way...  I think.

Actually, it isn't VoIP data yet, VoIP is Voice over Internet Protocol.
The 1000hz interupt is still just digitizing the audio off the PSTN
link. When it comes time to read/write VoIP data, it is likely 20ms of
audio, plus headers and IP encapsulation. If you are lucky, your LAN/WAN
card supports DMA and is reading the packet on it's own out of memory.

-- 
Steven Critchfield <critch at basesys.com>