Is 1000Hz kernel actually required?

Asterisk Asterisk Support
1

Hi

Are 1000Hz kernels still actually recommended or required for modern Asterisk installs or is this an obsolete issue of the past?

I’d like to install CentOS 7, Asterisk 13, FreePBX 13 on an Amazon EC2 t2.micro instance to use for a company PBX.

I’ve seen older posts indicating a 1000Hz kernel is important and was curious to know if updates in the technology have made that issue redundant as it adds a significant issue to the build.

Do FreePBX Distros with the O/S combined have 1000Hz kernels - anyone know?
(I intend to ask them as well but appreciate any learned response)

Unfortunately it’s not easy to convert a Distro ISO to EC2 AMI so have to manually build the Virtual Machine.

Any thoughts. comments, suggestions?

Thanks and regards
Sean

2

The timerfd module uses a standard interface provided by the Linux kernel, timerfd. If it provides accurate timing then it doesn’t matter. That’s the only requirement - that if it says for example it needs a wakeup at 20ms that it gets it (plus or minus a bit is fine but the more accurate the better). If it gets it all over the map then certain things can sound… weird.

3

Thanks heaps for the reply.

I interpret that to mean that it’s no longer an issue assuming modern machines, virtual or otherwise, should have accurate timers.

I hope that’s a safe assumption.

4

Virtual machines, unless the whole system is specially optimised for real time guests, generally DO NOT keep accurate time on a 20ms timescale. It is even worse if a VM has to be moved between hosts. What they tend to do is to fake the time seen by the VM so that it is well behaved on a time scale of seconds to minutes.

Tickless kernels also distort time keeping in order to minimise the number of reschedules.

5

Ultimately you have to do tests under your virtualization environment to see the behavior that occurs and how well it performs.