[asterisk-users] Is there real benefits on a SMP machine for Asterisk?

[Gordon Henderson]

On Fri, 12 Oct 2007, Tilghman Lesher wrote:

> On Friday 12 October 2007 10:29:24 Philipp Kempgen wrote:
>> Atis Lezdins wrote:
>>> I have 8-core system that has web interface + sql + java + some other
>>> stuff running, and at 30 simultenous calls i get loadavg maximum of 3.
>>
>> I wouldn't be too happy about a system with a
>> loadavg of 3.
>
> I dunno, 3 wouldn't be terrible on a 4 processor or 8 processor system, which
> isn't getting to be nearly as rare as it once was.

Don't get too hung-up on load average under Linux. It's not always 
indicative of the real "load" on the machine, it merely indicates the 
number of processes running, or avalable to run - so if a process is 
waiting on IO, it's 'running' and will get counted. I've seen servers (non 
asterisk) with huge load averages but ones which were still usable because 
the processes were waiting on IO from a slow device, (eg. remote NFS 
mounts) so there was plenty of CPU left for computational tasks, etc.

So 3 threads reading or writing to/from a TDM card might well spend most 
of their time waiting for the IO to complete (clock in/out the A/D, A/D 
convertors for example), give a load avg. of 3, yet the CPU should be 
avalable for other tasks like shoveling RTP data over Ethernet for 
example...

Gordon