Jitter buffer running high

[Konrad Viebahn]

Hi all,
My "headless" jamulus server is running on Ubuntu 18.04 on a hired virtual server. The ping is great (~6 ms from Switzerland to Frankfurt) but unfortunately the jitter buffer is running high (>7), such that the overall delay is much worse than for other servers (which have the same ping and jitter buffer < 3).
I've tried running the process with various users (incl root) but no change.
The process is constantly running and if one client is connected running top yields 8.6% CPU usage and 5.5% Mem usage. When two clients are connected the CPU goes up to 13.5%.
I've tried increasing 'niceness' beyond 0 but it seems to be limited to 0 (even with root privileges).
I configured the server using the unit file

[Unit]
Description=Jamulus-Server
After=network.target

[Service]
Type=simple
User=jamulus
Group=nogroup
NoNewPrivileges=true
ProtectSystem=true
ProtectHome=true
Nice=-20
IOSchedulingClass=realtime
IOSchedulingPriority=0

ExecStart=/usr/local/bin/Jamulus -s -n -e jamulus.fischvolk.de -o "yourServerName;yourCity;[country ID]"

Restart=on-failure
RestartSec=30
StandardOutput=journal
StandardError=inherit
SyslogIdentifier=jamulus

[Install]
WantedBy=multi-user.target

with the appropriate changes.
I was wondering why the niceness is not -20 (although it is configured such in the unit file).

Any ideas?

Cheers,
Konrad

[Gilgongo]

This sounds like there may be some I/O contention in the VM you are running the server on. Perhaps contact your ISP to ask?