mwan3 memory usage

Ravi Paluri (QUIC) quic_rpaluri at
Thu Jun 15 03:58:21 PDT 2023

    We have enabled mwan3 (version 2.11.4) functionality with OpenWRT version 22.03 and we see that four mwan3rtmon processes are running, two each for IPv4 and IPv6.
Whereas with mwan3 (version 2.8.16) that came with OpenWRT version 19.07, has only one process for mwan3rtmon running for both IPv4 and IPv6.
This has caused an increased memory usage on OpenWRT version 22.03 by 3 times when compared to OpenWRT version 19.07.
This is a huge concern for us as we have limited memory on our router product.

On debugging further, we see that mwan3rtmon script is invoking a child process, the reason behind observing two processes per each IP type. 
Refer(line number 155) at 
Can we know the reason behind creating child processes? 
To reduce memory usage, if we disable creation of child process, what functionality of mwan3 will be affected?

Also, is it recommended to use mwan3 (version 2.8.16) with OpenWRT version 22.03 as this has no child processes and only one mwan3rtmon process for both IPv4 and IPv6?

Below is the observation captured from device.

root at OpenWrt:/# ps w |grep mwan
22963 root      1672 S    {mwan3rtmon} /bin/sh /usr/sbin/mwan3rtmon

root at OpenWrt:/# ps w | grep mwan
2071 root      2332 S    /bin/sh /usr/sbin/mwan3rtmon ipv4
2072 root      2352 S    /bin/sh /usr/sbin/mwan3rtmon ipv6
2169 root      2296 S    /bin/sh /usr/sbin/mwan3rtmon ipv6
2176 root      2296 S    /bin/sh /usr/sbin/mwan3rtmon ipv4


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