On Thu, 25 Feb 2010, Vinícius Fontes wrote:
----- "Shaun Ruffell" <sruff...@digium.com> escreveu:
On 02/25/2010 11:19 AM, Vinícius Fontes wrote:
I'm playing around with an ALIX 2D2 board
(http://www.pcengines.ch/alix2d2.htm). It's a fanless, x86 system
using an AMD Geode processor with 256MB of RAM. Also available are two
network interfaces, two USB ports and one serial port (no keyboard or
VGA). I'm using the Voyage Linux distro, which basically is Debian
Lenny optimized for this board.
Asterisk 1.6.1.12 runs fine on the system. The only issue I'm having
is with MeetMe(). As there's no DAHDI devices attached, I'm running
dahdi_dummy. Audio gets all choppy on MeetMe(), but works fine for
other applications such as Playback(). SIP calls also work fine.
Most probably it's a timing issue. I connected an Astribank unit
with 16 FXS in order to provide timing, and after that I get crystal
clear audio on MeetMe().
Of course I wouldn't like to have an expensive Astribank attached to
the ALIX board just to provide timing. So my question is: is there any
way to improve dahdi_dummy's performance, or maybe some other way to
get this to work without the need for a physical DAHDI device?
What version of DAHDI are you using? As long as the host kernel is
able to accurately keep accurate wall time, I'm not aware of any
conditions that would prevent dahdi_dummy in dahdi-linux 2.2.1 from
working fine, so I'm very curious if this isn't the case. In fact, in
the trunk of dahdi-linux dahdi_dummy.ko is off by default and dahdi.ko
will be able to keep time regardless of whether there are any physical
spans connected or configured.
Sorry, forgot to include the DAHDI version.
voyage:~# dahdi_cfg -tv
DAHDI Tools Version - 2.2.1
DAHDI Version: 2.2.1
Echo Canceller(s):
Configuration
======================
I'm almost sure this board's RTC is not very accurate. Is there any way
to measure the RTC's accuracy?
I use these boards too. Brilliant little things. 5 watts and 80+
concurrent calls handling media before they fall over! Not much good for
transcoding though...
http://unicorn.drogon.net/cutie.jpg
However I have a slightly different approach in that I have my own
semi-custom Linux for them which runs entirely in RAM. I also
custom-compile the kernel for the architecture, and have compiled up dhadi
and asterisk specifically for that CPU too. (Read my earlier whinges about
it some time back!)
dsx$ df -h
Filesystem Size Used Avail Use% Mounted on
/dev/ram0 136M 79M 58M 58% /
/dev/hda3 189M 95M 95M 50% /data
dahdi_dummy on my systems use the high resolution timer and not RTC:
dahdi: Telephony Interface Registered on major 196
dahdi: Version: 2.2.0-rc2
dahdi_dummy: Trying to load High Resolution Timer
dahdi_dummy: Initialized High Resolution Timer
dahdi_dummy: Starting High Resolution Timer
dahdi_dummy: High Resolution Timer started, good to go
Other than a few quick tests, I've not really run many meetmes on one, but
I have a few dozen of these out in the world with clients so I don't
really know what they're doing with them... However they all use IAX
trunking which I understand requires timing too.
There's a few tweaks you can do to the system even running the distro
you're using - make sure no extra services are running - make sure logging
is minimal and not using fsync on every write (see your syslog config
file), mount partitions with the noatime and nodiratime flags - use as
fast a CF card as you can get, and so on. (Google for tuning hints for
systems like the Acer Aspire One and other similar laptops with SSDs and
so on)
Output of ps ax:
PID TTY STAT TIME COMMAND
1 ? Ss 0:01 init [2]
2 ? S< 0:00 [kthreadd]
3 ? S< 0:00 [ksoftirqd/0]
4 ? S< 0:00 [events/0]
5 ? S< 0:00 [khelper]
60 ? S< 0:00 [kblockd/0]
67 ? S< 0:00 [khubd]
106 ? S 0:00 [pdflush]
108 ? S< 0:00 [kswapd0]
153 ? S< 0:00 [aio/0]
737 ? S 0:00 [pdflush]
1006 ? Ss 0:00 /sbin/syslogd
1010 ? Ss 0:00 /sbin/klogd -x
1021 ? Ss 0:00 /usr/sbin/sshd
1028 ? Ss 0:00 /usr/local/apache2/bin/httpd -k start
1042 ? Ss 0:00 /usr/sbin/ntpd -p /var/run/ntpd.pid -g
1047 ? Ssl 0:00 /usr/sbin/asterisk -p
1086 ? Ss 0:00 /usr/sbin/cron
1099 ttyS0 Ss 0:00 /bin/login --
1323 ? S 0:00 /usr/local/apache2/bin/httpd -k start
2089 ttyS0 S+ 0:00 -bash
2094 ? Ss 0:00 sshd: d...@pts/0
2098 pts/0 Ss 0:00 login -h yakko.drogon.net -p -f
2099 pts/0 R 0:00 -bash
2109 pts/0 R+ 0:00 ps ax
Not sure I can get it any more minimal than that!
Gordon--
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