[asterisk-biz] Performance on Pentium Dual Core CPUs

[Boris Bakchiev]

Kevin,

Just to prove the point that Asterisk is great I got 2 SQL servers
(couple of 6x cpu xeon servers) to host as sip peers.
Those are much faster then the previous Celerons.

The results kinda puzzled me.
With 300 calls I get:
Cpu0  : 21.9% us, 10.0% sy,  0.0% ni, 60.2% id,  0.0% wa,  0.0% hi,
8.0% si
Cpu1  :  0.0% us,  1.0% sy,  0.0% ni, 99.0% id,  0.0% wa,  0.0% hi,
0.0% si

Just got a friend in US who works for ITSP there to test the same
scenario with Digium codec on almost identical server (same CPU, mem,
motherboard)
Cpu0  : 16.4% us
Cpu1  :  0.5% us

So it appears that Digium codec is better performing then IPP based one.

Show channels shows:
600 active channels
300 active calls

Sip show channels shows 300 alaw and 300 g729 channels.

Iptraf shows:
Incoming rates:    3510.0 kbits/sec
6200.2 packets/sec
Outgoing rates:    1284.1 kbits/sec
			 1114.4 packets/sec

And I can see a flurry of the traffic on the interfaces.

As I'm writing, SMP rebalanced the load so it is now:
Cpu0  : 10.9% us, 11.9% sy,  0.0% ni, 71.1% id,  0.0% wa,  0.0% hi,
6.0% si
Cpu1  :  8.4% us,  4.9% sy,  0.0% ni, 86.7% id,  0.0% wa,  0.0% hi,
0.0% si

Are my missing something?
Perhaps the conditions are "near perfect" but the encoder and decoder
still doing they job and on take 10% of the systems capacity.

I think the whole test was affected by the CPU's cache. I think all the
data was cached and since server was doing nothing else but transcoding
all active code and data was cached in CPU's L2.

This makes all kind of benchmarking useless as far as I can see as it is
almost impossible to replicate a working system with test tools.

I welcome the idea of hardware G729 as it would be a more sensible
approach for production systems.

Regards


-----Original Message-----
From: asterisk-biz-bounces at lists.digium.com
[mailto:asterisk-biz-bounces at lists.digium.com] On Behalf Of Kevin P.
Fleming
Sent: Monday, 5 June 2006 02:53
To: Commercial and Business-Oriented Asterisk Discussion
Subject: Re: [asterisk-biz] Performance on Pentium Dual Core CPUs


----- Sergey Kuznetsov <asterisk_biz at deeptown.org> wrote:

> Can you share your expectations how many G729 transcodings can be done
> 
> on dual dual-core Opterons or P4 with 4 Gb of memory on SIP-to-SIP 
> environments ( no TDM or echocancelers involved)
> My guess is about 250-300 simultaneous calls.

I don't have any first-hand experience, as we don't do performance
benchmarking like that.

In any case, the amount of memory will make no difference at all. The
clock speed of the CPUs and the speed of the memory bus will be the
determining factors, so realistically I would expect the Opterons to
perform better than P4s due to their much more efficient memory
subsystem.

However, I can say that I doubt any existing PC-type platform will be
able to achieve 250 or 300 simultaneous G.729 transcodes; any single box
that could handle that would cost far more than a pair of
lower-performance systems to do the same thing (think scaling
horizontally, not vertically). In addition, when Digium releases the
hardware G.729 transcoder board in the near future this will become less
of an issue for deployments of that size.

-- 
Kevin P. Fleming
Senior Software Engineer
Digium, Inc.

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