将 Ubuntu 升级到 16.04 LTS 后，我发现 Ubuntu 的加载速度与 14.04 相比明显变慢。这意味着 PC 开机后需要更多时间加载登录屏幕，输入密码和填充 Ubuntu 桌面之间的间隔也更长。有办法解决这个问题吗？
编辑：添加systemd-analyze blame输出。
14.737s networking.service
13.727s apport.service
13.666s speech-dispatcher.service
11.593s dev-sda3.device
9.058s iio-sensor-proxy.service
9.055s rsyslog.service
9.029s systemd-user-sessions.service
8.979s thermald.service
8.059s NetworkManager-wait-online.service
7.600s apparmor.service
7.314s accounts-daemon.service
4.996s grub-common.service
4.665s irqbalance.service
4.638s ondemand.service
4.155s console-setup.service
3.771s lightdm.service
3.414s systemd-tmpfiles-setup.service
2.914s NetworkManager.service
2.017s systemd-backlight@backlight:intel_backlight.service
1.760s systemd-udevd.service
1.479s resolvconf.service
1.451s systemd-tmpfiles-setup-dev.service
1.442s ModemManager.service
lines 1-23...skipping...
14.737s networking.service
13.727s apport.service
13.666s speech-dispatcher.service
11.593s dev-sda3.device
9.058s iio-sensor-proxy.service
9.055s rsyslog.service
9.029s systemd-user-sessions.service
8.979s thermald.service
8.059s NetworkManager-wait-online.service
7.600s apparmor.service
7.314s accounts-daemon.service
4.996s grub-common.service
4.665s irqbalance.service
4.638s ondemand.service
4.155s console-setup.service
3.771s lightdm.service
3.414s systemd-tmpfiles-setup.service
2.914s NetworkManager.service
2.017s systemd-backlight@backlight:intel_backlight.service
1.760s systemd-udevd.service
1.479s resolvconf.service
1.451s systemd-tmpfiles-setup-dev.service
1.442s ModemManager.service
1.208s plymouth-start.service
1.035s systemd-journald.service
1.000s systemd-modules-load.service
918ms keyboard-setup.service
905ms gpu-manager.service
696ms upower.service
688ms udisks2.service
678ms systemd-update-utmp.service
583ms dev-disk-by\x2duuid-b6b1a8eb\x2d15a0\x2d4f95\x2da7d4\x2df5291de0b7a8.swap
541ms avahi-daemon.service
502ms dev-mqueue.mount
422ms ufw.service
377ms polkitd.service
332ms colord.service
326ms kmod-static-nodes.service