[asterisk-users] Dahdi for meetme on AMD64 arch?

[Johan Wilfer]

I'm in the process of replacing an old server with a new one and are
making som changes in the infrastructure, the biggest change in my eyes
is moving from i386 to AMD64 arch. Yesterday I began migrating some
users from the old to the new server.

After only 57 concurrent calls in abount 13 conferences the sound are
losing quality.
The server uses dahdi 2.6.0 for timing but no dahdi hardware.

dahdi_test gives results like this when the server is used like that:
100.000% 99.999% 99.994% 99.998% 99.999% 99.616% 99.614% 99.997%
99.998% 99.618% 99.615% 99.994% 99.987% 99.626% 99.628% 99.993%
99.626% 100.000% 100.000% 99.622% 99.999% 99.607% 99.604% 99.627%
99.621% 99.629% 99.627% 99.998% 99.622% 99.995% 99.621% 99.996%

Results from dahdi_test with only some calls active:
99.999% 99.999% 99.990% 99.998% 99.999% 99.995% 99.995% 99.993%
99.997% 99.993% 99.999% 99.998% 99.996% 99.996% 99.998% 99.998%
99.991% 99.998% 99.995% 99.995% 99.987% 99.985% 99.996% 99.995%

Looking at the cacti graphs the kernel uses 100% cpu (total 400% with 4
processor cores), when the problem above is present. Top does not show
this kernel-cpu that cacti shows, but this maybe is by design? Asterisk
is using about 15% cpu.

top - 19:32:06 up 20:57,  1 user,  load average: 0.00, 0.00, 0.00
Tasks: 213 total,   1 running, 212 sleeping,   0 stopped,   0 zombie
Cpu(s):  7.4%us, 29.6%sy,  0.0%ni, 55.3%id,  0.0%wa,  0.0%hi,  7.7%si, 
0.0%st
Mem:  12299332k total,  3967800k used,  8331532k free,   251432k buffers
Swap: 19529720k total,        0k used, 19529720k free,  2919456k cached

  PID USER      PR  NI  VIRT  RES  SHR S %CPU %MEM    TIME+  COMMAND
30666 root       0 -20  539m  25m 6600 S   15  0.2   6:55.01 asterisk
  738 root      20   0 19184 1444 1004 R    1  0.0   0:00.08 top


The old server (i386 Debian 5: Linux 2.6.26-2-openvz-686) can have 320
calls in conferences without this problem.
The new server (amd64 Debian 6: Linux 2.6.32-5-openvz-amd64) show these
problems after 50 calls..

Old server:
Hp dl360g5, 4 cpu Xeon E5420, 2.50GHz
run i386 with PAE and OpenVZ, Debian Lenny
uses the broadcom nic's on the motherboard
asterisk 1.4.42 in openvz container (uses /dev/dahdi for timing)
cacti shows cpu in kernel mode 80% with 320 active calls in conferences

New server:
Hp dl360g7, 4 cpu Xeon E5520, 2.27GHz
run amd63 with OpenVZ, Debian Squeeze
uses Intel nic's 82571EB for offloading the processor + nic bonding in
the kernel for failover.
asterisk 1.4.42 in openvz container (uses /dev/dahdi for timing)
cacti show cpu in kernel mod 100% with 57 active calls in conferences

This is a puzzle to me..
 - Does anyone have experience with amd64 arch and dahdi for timing?
 - Can Dahdi om amd64 be responsible for the high cpu in kernel mode?

 - I have a spare Digium TE220, would it offload the server to use it as
a timing source only?
 - How do I debug the high cpu usage by the kernel, can I break this
down by module in some way?


Many, many thanks!

-- 
Johan Wilfer                 email: johan at jttech.se
JT Tech | Developer          webb: http://jttech.se