如何改善 Ubuntu 20.04 的启动时间？
我systemd-analyze在终端中使用命令，结果如下
启动耗时 5.114 秒（内核）+ 45.128 秒（用户空间）= 50.243 秒 graphic.target 在用户空间耗时 44.915 秒后达到
然后我使用了，systemd-analyze blame结果如下：
26.151s plymouth-quit-wait.service >
12.393s snapd.service >
9.588s dev-sda7.device >
9.237s systemd-journal-flush.service >
8.921s NetworkManager-wait-online.service >
8.311s networkd-dispatcher.service >
6.717s winbind.service >
5.311s udisks2.service >
4.917s dev-loop10.device >
4.078s NetworkManager.service >
3.941s accounts-daemon.service >
3.664s dev-loop11.device >
3.640s dev-loop9.device >
3.584s dev-loop3.device >
3.475s dev-loop6.device >
3.445s polkit.service >
3.387s dev-loop13.device >
3.341s dev-loop4.device >
3.267s dev-loop0.device >
3.116s dev-loop1.device >
3.057s dev-loop8.device >
2.894s dev-loop12.device >
2.782s avahi-daemon.service >
2.781s bluetooth.service >
2.718s dev-loop5.device >
2.652s dev-loop2.device >
2.579s switcheroo-control.service >
2.568s thermald.service >
2.564s wpa_supplicant.service >
2.560s systemd-logind.service >
2.547s grub-initrd-fallback.service >
2.447s dev-loop7.device >
2.387s grub-common.service >
1.943s secureboot-db.service >
1.846s apport.service >
1.712s gpu-manager.service >
1.470s ModemManager.service >
1.381s [email protected] >
1.276s e2scrub_reap.service >
1.128s gdm.service >
1.092s systemd-resolved.service >
1.058s rsyslog.service >
992ms systemd-tmpfiles-setup.service >
905ms laptop-mode.service >
889ms systemd-rfkill.service >
846ms upower.service >
842ms fwupd.service >
728ms systemd-udevd.service >
698ms apparmor.service >
658ms packagekit.service >
620ms systemd-backlight@backlight:intel_backlight.service >
620ms pppd-dns.service >
583ms systemd-fsck@dev-disk-by\x2duuid-3451\x2d17B3.service >
552ms snapd.apparmor.service >
508ms snap-core-9804.mount >
493ms systemd-modules-load.service >
475ms keyboard-setup.service >
473ms systemd-journald.service >
471ms snap-vlc-1700.mount >
462ms colord.service >
448ms systemd-udev-trigger.service >
447ms snap-snap\x2dstore-433.mount >
434ms dev-disk-by\x2duuid-faed61cc\x2d41cb\x2d462b\x2dbec6\x2d0515af804cd7.sw>
433ms snap-snap\x2dstore-467.mount >
399ms snap-chromium-1260.mount >
396ms snap-snapd-8790.mount >
387ms snapd.seeded.service >
380ms snap-gnome\x2d3\x2d34\x2d1804-36.mount >
372ms systemd-tmpfiles-setup-dev.service >
323ms snap-core18-1885.mount >
319ms systemd-sysusers.service >
317ms snap-canonical\x2dlivepatch-95.mount >
310ms snap-core18-1705.mount >
280ms systemd-sysctl.service >
267ms snap-snapd-7264.mount >
252ms plymouth-start.service >
250ms openvpn.service >
238ms systemd-timesyncd.service >
232ms systemd-random-seed.service >
217ms snap-onlyoffice\x2ddesktopeditors-45.mount >
205ms [email protected] >
203ms systemd-remount-fs.service >
197ms setvtrgb.service >
190ms systemd-update-utmp-runlevel.service >
178ms lmt-poll.service >
173ms geoclue.service >
172ms systemd-user-sessions.service >
155ms dev-hugepages.mount >
154ms dev-mqueue.mount >
153ms snap-gnome\x2d3\x2d34\x2d1804-24.mount >
153ms sys-kernel-debug.mount >
152ms sys-kernel-tracing.mount >
148ms kmod-static-nodes.service >
133ms snap-gtk\x2dcommon\x2dthemes-1506.mount >
84ms kerneloops.service >
66ms ufw.service >
46ms [email protected] >
43ms systemd-update-utmp.service >
41ms boot-efi.mount >
33ms console-setup.service >
14ms alsa-restore.service >
12ms plymouth-read-write.service >
11ms rtkit-daemon.service >
5ms sys-fs-fuse-connections.mount >
4ms sys-kernel-config.mount >
3ms snapd.socket >
lines 84-106/106 (END)
190ms systemd-update-utmp-runlevel.service
178ms lmt-poll.service
173ms geoclue.service
172ms systemd-user-sessions.service
155ms dev-hugepages.mount
154ms dev-mqueue.mount
153ms snap-gnome\x2d3\x2d34\x2d1804-24.mount
153ms sys-kernel-debug.mount
152ms sys-kernel-tracing.mount
148ms kmod-static-nodes.service
133ms snap-gtk\x2dcommon\x2dthemes-1506.mount
84ms kerneloops.service
66ms ufw.service
46ms [email protected]
43ms systemd-update-utmp.service
41ms boot-efi.mount
33ms console-setup.service
14ms alsa-restore.service
12ms plymouth-read-write.service
11ms rtkit-daemon.service
5ms sys-fs-fuse-connections.mount
4ms sys-kernel-config.mount
3ms snapd.socket
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lines 84-106/106 (END)
190ms systemd-update-utmp-runlevel.service
178ms lmt-poll.service
173ms geoclue.service
172ms systemd-user-sessions.service
155ms dev-hugepages.mount
154ms dev-mqueue.mount
153ms snap-gnome\x2d3\x2d34\x2d1804-24.mount
153ms sys-kernel-debug.mount
152ms sys-kernel-tracing.mount
148ms kmod-static-nodes.service
133ms snap-gtk\x2dcommon\x2dthemes-1506.mount
84ms kerneloops.service
66ms ufw.service
46ms [email protected]
43ms systemd-update-utmp.service
41ms boot-efi.mount
33ms console-setup.service
14ms alsa-restore.service
12ms plymouth-read-write.service
11ms rtkit-daemon.service
5ms sys-fs-fuse-connections.mount
4ms sys-kernel-config.mount
3ms snapd.socket
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lines 84-106/106 (END)
190ms systemd-update-utmp-runlevel.service >
178ms lmt-poll.service >
173ms geoclue.service >
172ms systemd-user-sessions.service >
155ms dev-hugepages.mount >
154ms dev-mqueue.mount >
153ms snap-gnome\x2d3\x2d34\x2d1804-24.mount >
153ms sys-kernel-debug.mount >
152ms sys-kernel-tracing.mount >
148ms kmod-static-nodes.service >
133ms snap-gtk\x2dcommon\x2dthemes-1506.mount >
84ms kerneloops.service >
66ms ufw.service >
46ms [email protected] >
43ms systemd-update-utmp.service >
41ms boot-efi.mount >
33ms console-setup.service >
14ms alsa-restore.service >
12ms plymouth-read-write.service >
11ms rtkit-daemon.service >
5ms sys-fs-fuse-connections.mount >
4ms sys-kernel-config.mount >
lines 84-105/106 99%
190ms systemd-update-utmp-runlevel.service >
178ms lmt-poll.service >
173ms geoclue.service >
172ms systemd-user-sessions.service >
155ms dev-hugepages.mount >
154ms dev-mqueue.mount >
153ms snap-gnome\x2d3\x2d34\x2d1804-24.mount >
153ms sys-kernel-debug.mount >
152ms sys-kernel-tracing.mount >
148ms kmod-static-nodes.service >
133ms snap-gtk\x2dcommon\x2dthemes-1506.mount >
84ms kerneloops.service >
66ms ufw.service >
46ms [email protected] >
43ms systemd-update-utmp.service >
41ms boot-efi.mount >
33ms console-setup.service >
14ms alsa-restore.service >
12ms plymouth-read-write.service >
11ms rtkit-daemon.service >
lines 84-103/106 97%
203ms systemd-remount-fs.service >
197ms setvtrgb.service >
190ms systemd-update-utmp-runlevel.service >
178ms lmt-poll.service >
173ms geoclue.service >
172ms systemd-user-sessions.service >
155ms dev-hugepages.mount >
154ms dev-mqueue.mount >
153ms snap-gnome\x2d3\x2d34\x2d1804-24.mount >
153ms sys-kernel-debug.mount >
152ms sys-kernel-tracing.mount >
148ms kmod-static-nodes.service >
133ms snap-gtk\x2dcommon\x2dthemes-1506.mount >
84ms kerneloops.service >
66ms ufw.service >
46ms [email protected] >
43ms systemd-update-utmp.service >
41ms boot-efi.mount >
33ms console-setup.service >
14ms alsa-restore.service >
12ms plymouth-read-write.service >
11ms rtkit-daemon.service >
5ms sys-fs-fuse-connections.mount >
4ms sys-kernel-config.mount >
3ms snapd.socket >
我有什么选择可以进一步缩短启动时间？提前致谢。
有关所用硬件的更新：
戴尔 5521 笔记本电脑
Intel® Core™ i5-3337U CPU @ 1.80GHz × 4
英特尔® 高清显卡 4000 (IVB GT2)
16 GB 内存
1TB 硬盘