snom ONE Technical Manual - Atcom

28
Deploying the snom ONE IP Telephone System
Before (set to No):
After (set to Yes):
Performance
From this section, you can set performance-related settings.
■ Maximum Number of Calls: This setting defines the number of simultaneously calls allowed by
the system. Because every call requires a certain portion of the available CPU, allowing too many
calls will affect the quality of all ongoing calls. By limiting the number of calls on the CPU, you
can reject calls that would otherwise potentially degrade overall performance. On modern PCs, 100
or more calls can run on one computer; however, on an embedded system, you will probably have
much less CPU power and thereby increase the probability of running out of CPU power if you
allow that many calls. If this field is left blank, the key in the system will limit the calls, or the CPU
limitation, when reached, will limit the calls.
■ Processor Affinity Mask: This field allows the administrator to assign a particular CPU to the
pbxctrl system process. When using a multiple-core CPU, the operating system has to assign processes
to processors. By default, the operating system tries to balance out the load so that the overall
system performance is as fast as possible. However, the disadvantage with this approach is that the
whole process gets stuck for some time while moving the processes from one CPU to another. If
during that time the CPU should play out media, it will come across as stuttering and be perceived
as jitter coming from the system. In order to avoid this problem, bind the pbxctrl to one fixed
CPU. Depending on the operating system, you can do this manually or you can ask the system
processes to do this during startup. Changes to this field require a system restart.
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