Created attachment 161840 [details] screenshot shows zigzag profile of the network traffic SUMMARY *** The system monitor shows a zigzag (sawtooth) profile when downloading at a constant rate. Note, this only seems to happen on systems where the underlying kernel network driver doesn't allow adjusting the refresh frequency of the device transmission statistics. *** STEPS TO REPRODUCE 1. download at a constant rate, e.g. wget https://cdn.kernel.org/pub/linux/kernel/v6.x/linux-6.5.5.tar.xz 2. open the KDE system monitor and observe the network diagram OBSERVED RESULT zigzag profile, where the max is twice the download rate EXPECTED RESULT constant profile SOFTWARE/OS VERSIONS Linux/KDE Plasma: openSUSE 15.4 and 15.5 KDE Plasma Version: KDE Frameworks Version: 5.102.0 Qt Version: 5.15.8 ADDITIONAL INFORMATION The underlying problem seems to be with ksystemstats5 which calculates the download/upload rates using a hard-coded interval of 0.5s: https://github.com/KDE/ksystemstats/blob/master/plugins/network/NetworkManagerBackend.cpp#L20 // Update rate in ms static const int UpdateRate = 500; However, not all kernel network device driver support updating the refresh frequency of the received/sent byte statistics: # ethtool -c eth0 | grep stats-block-usecs stats-block-usecs: 0 # ethtool -C eth0 stats-block-usecs 500000 netlink error: Invalid argument # lspci | grep Ethernet 04:00.0 Ethernet controller: Broadcom Inc. and subsidiaries NetLink BCM57780 Gigabit Ethernet PCIe (rev 01) The update-frequency of the statistics of my eth0 device seems to be about 1s (checked via cat /proc/net/dev), which explains the zigzag profile (first 0.5s no change in received bytes --> 0 Mb/s, second 0.5s all bytes received in the whole second --> twice as much Mb/s).