asterisk users - Jan 2005 - Asterisk CPU priorities (nice?)

Had a good question for the list, it seems whenever I work in an
Asterisk console or on the machine normally I get jitters on any audio
going through it. Especially if you did file copies or a 'ps ax' for
example. I was wondering if there was a proper way to 'nice' the
asterisk proc's? Cisco does this for example to it's "EXEC"
and icmp
processes, I tried reniceing the asterisk processes with very bad
results, especially when I/O (voicemail, etc) comes into play. I'm not
swapping out or anything, ideas?

p.s. I searched the wiki but not exactly sure what to search for I
guess, I imagine someone out there has run into these issues?

	Matt

> Had a good question for the list, it seems whenever I work in an
> Asterisk console or on the machine normally I get jitters on any audio
> going through it. Especially if you did file copies or a 'ps ax'
for
> example. I was wondering if there was a proper way to 'nice' the
> asterisk proc's? Cisco does this for example to it's
"EXEC" and icmp
> processes, I tried reniceing the asterisk processes with very bad
> results, especially when I/O (voicemail, etc) comes into play. I'm not
> swapping out or anything, ideas?
> 
> p.s. I searched the wiki but not exactly sure what to search for I
> guess, I imagine someone out there has run into these issues?
Over the last couple of months there has been multiple postings relative
to changing the pci latency associated with the disk and pstn interfaces.
General comments tend to suggest the disk can consum hugh amounts of
time, impacting ethernet and/or pstn interfaces (and thus audio).

I've not played a lot with the latency settings, but understand its a
balancing act between specific devices on _your_ system (not necessarily
anyone elses). If you execute a "lspci -v" (as an example), you'll
see
the current pci latency settings.

Google should find several references.

Matt Schulte wrote:
> Had a good question for the list, it seems whenever I work in an
> Asterisk console or on the machine normally I get jitters on any audio
> going through it. Especially if you did file copies or a 'ps ax'
for
> example. I was wondering if there was a proper way to 'nice' the
> asterisk proc's? Cisco does this for example to it's
"EXEC" and icmp
> processes, I tried reniceing the asterisk processes with very bad
> results, especially when I/O (voicemail, etc) comes into play. I'm not
> swapping out or anything, ideas?
> 

Since VoIP is a real time activity, simple "nice" really isn't
enough.
What you should do is mark the Asterisk proccess as a real time task for 
the Linux kernel to schedule accordingly. You can do this with Asterisk 
by passing the "-p" option to the Asterisk command line.

A warning is due here: real time priority scheduled tasks are not 
something to be toyed with. You need to be root to be able to turn on 
this feature (meaning you have to be running Asterisk as root). A bug in 
Asterisk, a problem with mpg123 or a red alert on a FXO card can very 
well leave your system completly non responsive - so use with care.

Having said that, I've been running an Asterisk server on a machine 
which is also used as SOHO firewall and file server for year now and it 
works great.

Hope this helps,
Gilad

Joao Pereira wrote:
> Hello to all
> I would like to know if someone tried the VPT1000 WiFi phone from:
> http://pcphoneline.com/
Where do you see that it is a WiFi phone? That page says it uses USB to 
connect to your computer. In fact, there is no mention of WiFi or any 
802.11 on that page at all.