Since I configured a bridged interface, I noticed that the boot went from 3-4 seconds to about 20 seconds. Here are my investigations, the ifupdown-pre.service is to blame. But why ?
Note1 : I'm on Debian 11.4
Note2 : Apart of the tests below I did several other tests, with an empty bridge (e.g. without bridge_ports), with a bridge with only a dummy0 interface, ... Same result. It seems whenever there is a bridge it slows down ifupdown-pre.service, whatever the configuration of that bridge is.
1/ Without a bridge :
Code:
$ ls /etc/network/interfaces.d/
da200-enx3448ed795fcb
$ cat /etc/network/interfaces.d/da200-enx3448ed795fcb
allow-hotplug enx3448ed795fcb
iface enx3448ed795fcb inet static
address 192.168.137.2
netmask 255.255.255.0
$ systemd-analyze blame | head -n 3
3.701s plymouth-quit-wait.service
1.698s loadcpufreq.service
1.244s postfix@-.service
$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
(...)
2: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
(...)
3: enx3448ed795fcb: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel state DOWN group default qlen 1000
link/ether 34:48:ed:79:5f:cb brd ff:ff:ff:ff:ff:ff
inet 192.168.137.2/24 brd 192.168.137.255 scope global enx3448ed795fcb
valid_lft forever preferred_lft forever
2/ With a bridge :
My network files :
Code:
$ ls /etc/network/interfaces.d/
br0 da200-enx3448ed795fcb
$ cat /etc/network/interfaces.d/da200-enx3448ed795fcb
allow-hotplug enx3448ed795fcb
iface enx3448ed795fcb inet static
address 0.0.0.0
netmask 0.0.0.0
$ cat /etc/network/interfaces.d/br0
auto br0
iface br0 inet static
address 192.168.137.2
netmask 255.255.255.0
bridge_ports enx3448ed795fcb
bridge_maxwait 0
bridge_stp off
ifupdown-pre.service` now takes 18 seconds :
Code:
$ systemd-analyze blame | head -n 3
17.851s ifupdown-pre.service
2.707s plymouth-quit-wait.service
1.946s loadcpufreq.service
$ ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
(...)
2: wlp2s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
(...)
3: enx3448ed795fcb: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc fq_codel master br0 state DOWN group default qlen 1000
link/ether 34:48:ed:79:5f:cb brd ff:ff:ff:ff:ff:ff
4: br0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether 2e:55:46:7e:5c:1e brd ff:ff:ff:ff:ff:ff
inet 192.168.137.2/24 brd 192.168.137.255 scope global br0
valid_lft forever preferred_lft forever
$ systemd-analyze critical-chain
graphical.target @21.006s
└─multi-user.target @21.006s
└─plymouth-quit-wait.service @18.298s +2.707s
└─rc-local.service @18.247s +49ms
└─network-online.target @18.241s
└─network.target @18.241s
└─networking.service @18.173s +67ms
└─ifupdown-pre.service @321ms +17.851s
└─systemd-udev-trigger.service @251ms +68ms
└─systemd-udevd-kernel.socket @244ms
└─system.slice @185ms
└─-.slice @185ms
# journalctl -b -u ifupdown-pre.service
22 -- Journal begins at Tue 2022-07-12 21:45:01 WAT, ends at Sat 2022-08-27 09:26:02 WAT. --
23 août 27 09:25:00 xps13-7390 systemd[1]: Starting Helper to synchronize boot up for ifupdown...
24 août 27 09:25:00 xps13-7390 sh[347]: ifquery: parsing file /etc/network/interfaces.d/br0
25 août 27 09:25:00 xps13-7390 sh[347]: ifquery: parsing file /etc/network/interfaces.d/da200-enx3448ed795fcb
26 août 27 09:25:18 xps13-7390 systemd[1]: Finished Helper to synchronize boot up for ifupdown.
