从 16.04 更新到 18.04 后，启动过程感觉很慢：
systemd-analyze time
Startup finished in 34.455s (kernel) + 23.569s (userspace) = 58.025s
graphical.target reached after 17.137s in userspace
systemd-analyze blame
22.057s [email protected]
10.830s networking.service
5.162s plymouth-quit-wait.service
1.565s vmware.service
1.344s NetworkManager-wait-online.service
1.231s [email protected]
895ms fwupd.service
685ms ufw.service
670ms dev-mapper-rootvg\x2dlv_root.device
659ms dev-mapper-rootvg\x2dlv_usr.device
628ms mpd.service
607ms keyboard-setup.service
537ms [email protected]
501ms vmware-workstation-server.service
444ms vmware-USBArbitrator.service
394ms networkd-dispatcher.service
388ms ModemManager.service
379ms udisks2.service
330ms NetworkManager.service
308ms tlp.service
299ms accounts-daemon.service
256ms systemd-journal-flush.service
245ms auditd.service
240ms grub-common.service
235ms systemd-logind.service
234ms snapd.service
227ms apport.service
225ms virtualbox.service
207ms apache2.service
205ms avahi-daemon.service
176ms gpu-manager.service
175ms sysstat.service
174ms alsa-restore.service
168ms pppd-dns.service
159ms rsyslog.service
152ms lvm2-pvscan@8:4.service
145ms [email protected]
134ms upower.service
132ms systemd-timesyncd.service
130ms apparmor.service
125ms systemd-resolved.service
115ms snap-core-4571.mount
115ms teamviewerd.service
85ms snap-keepassxc-37.mount
81ms snap-core-4486.mount
我不确定如何改进 usb_modeswitch 和 networking.service。你有什么建议吗？