<html dir="ltr"> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> </head> <body style="text-align:left; direction:ltr;" bgcolor="#ffffff" text="#2e3436" link="#1b6acb" vlink="#2e3436"> Hi Folks, I'm trying to optimise our boot process and have started to look at the time it takes for the network to come up (a single interface to be routable) when using systemd-networkd: root@HOST:/# systemd-analyze critical-chain network-online.target --no- pager The time after the unit is active or started is printed after the "@" character. The time the unit takes to start is printed after the "+" character. network-online.target @4.144s └─systemd-networkd-wait-online.service @615ms +3.527s └─systemd-networkd.service @582ms +30ms └─systemd-tmpfiles-setup.service @315ms +63ms └─local-fs.target @314ms root@HOST:/# So, here systemd-networkd-wait-online.service seems to run for 3.5s - I had initially though this is due to the RTT for DHCP but in doing a packet capture for DHCP this isn't the case: me@DHCP-SERVER:~$ sudo tshark -i eth0 -f "(ether src 28:16:a8:fd:53:77 || ether dst 28:16:a8:fd:53:77) && (port 67 || port 68)" Running as user "root" and group "root". This could be dangerous. Capturing on 'eth0' 1 0.000000000 0.0.0.0 → 255.255.255.255 DHCP 333 DHCP Discover - Transaction ID 0x5c9e3cd0 2 0.000157300 192.168.3.3 → 192.168.3.16 DHCP 373 DHCP Offer - Transaction ID 0x5c9e3cd0 3 0.000695601 0.0.0.0 → 255.255.255.255 DHCP 345 DHCP Request - Transaction ID 0x5c9e3cd0 4 0.000771901 192.168.3.3 → 192.168.3.16 DHCP 373 DHCP ACK - Transaction ID 0x5c9e3cd0 So, that's 700us from discover to ack. We have 3 network interfaces, only enP8p1s0f0np0 is of use to us: root@HOST:/# networkctl status -a --no-pager ● 1: lo Link File: /usr/lib/systemd/network/99-default.link Network File: n/a Type: loopback State: carrier (unmanaged) Address: 127.0.0.1 ::1 ● 2: enP8p1s0f0np0 Link File: /usr/lib/systemd/network/99-default.link Network File: /etc/systemd/network/wired.network Type: ether State: routable (configured) Path: platform-60400000.pcie-pci-0008:01:00.0 Driver: bnxt_en HW Address: 28:16:a8:fd:53:77 Address: 192.168.3.16 2001:db8:0:1:2a16:a8ff:fefd:5377 fe80::2a16:a8ff:fefd:5377 Gateway: 192.168.3.1 fe80::7683:efff:fed4:935 DNS: 10.50.10.50 10.50.50.50 NTP: 10.222.184.12 Connected To: localhost on port Ethernet31/1 ● 3: enP8p1s0f1np0 Link File: /usr/lib/systemd/network/99-default.link Network File: n/a Type: ether State: off (unmanaged) Path: platform-60400000.pcie-pci-0008:01:00.1 Driver: bnxt_en HW Address: 00:10:18:ad:05:01 root@HOST:/# Networking configuration looks like this: root@HOST:/# cat /etc/systemd/network/wired.network [Match] Name=eth* en* [Network] DHCP=v4 root@HOST:/# cat /etc/systemd/network/ blacklist_interfaces.network wired.network root@HOST:/# cat /etc/systemd/network/blacklist_interfaces.network [Match] Name=enP8p1s0f1* [Network] DHCP=no LinkLocalAddressing=no IPv6AcceptRA=false [Link] RequiredForOnline=no Unmanaged=yes root@HOST:/# Our version is: root@HOST:/# systemctl --version systemd 239 +PAM +AUDIT +SELINUX +IMA -APPARMOR +SMACK +SYSVINIT +UTMP +LIBCRYPTSETUP -GCRYPT -GNUTLS -ACL +XZ -LZ4 -SECCOMP +BLKID -ELFUTILS +KMOD -IDN2 -IDN -PCRE2 default-hierarchy=unified root@HOST:/# I've had a look at <a href="https://github.com/systemd/systemd/blob/v239/src/network/wait-online/wait-online.c" class="evo-awrap" style="font-family: monospace;">https://github.com/systemd/systemd/blob/v239/src/network/wait-online/wait-online.c</a> and it really doesn't do much other than wait for the operational state to be "routable". Can anyone offer any suggestions for where I should look to try to speed things up here? Thanks! Peter. </body> </html>