我正在运行 Windows 10 和 Ubuntu 16.04 的双启动桌面。虽然我的 Windows 启动速度非常快，但我的 Ubuntu 启动时间太长了。为了调查，我运行dmesg并发现了一些我认为可能是原因的消息。但是，我不确定这是否是事实，我是否可以做些什么来加快启动速度
以下是 dmesg 的最后几行
[ 14.635266] Adding 4881404k swap on /dev/sda5. Priority:-1 extents:1 across:4881404k FS
[ 22.877684] IPv6: ADDRCONF(NETDEV_UP): wlp3s0: link is not ready
[ 22.884878] IPv6: ADDRCONF(NETDEV_UP): wlp3s0: link is not ready
[ 22.901317] IPv6: ADDRCONF(NETDEV_UP): enp6s0: link is not ready
[ 22.901971] atl1c 0000:06:00.0: atl1c: enp6s0 NIC Link is Up<1000 Mbps Full Duplex>
[ 24.055406] IPv6: ADDRCONF(NETDEV_UP): wlp3s0: link is not ready
[ 27.733484] audit_printk_skb: 42 callbacks suppressed
[ 27.733487] audit: type=1400 audit(1495500079.496:26): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/proc/1080/status" pid=1080 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=121 ouid=121
[ 27.733510] audit: type=1400 audit(1495500079.496:27): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/sys/devices/system/node/" pid=1080 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=121 ouid=0
[ 27.733538] audit: type=1400 audit(1495500079.496:28): apparmor="DENIED" operation="open" profile="/usr/sbin/mysqld" name="/proc/1080/status" pid=1080 comm="mysqld" requested_mask="r" denied_mask="r" fsuid=121 ouid=121
[ 304.593596] SGI XFS with ACLs, security attributes, realtime, no debug enabled
[ 304.631262] JFS: nTxBlock = 8192, nTxLock = 65536
[ 304.666374] ntfs: driver 2.1.32 [Flags: R/O MODULE].
[ 304.704295] QNX4 filesystem 0.2.3 registered.
[ 304.817377] raid6: sse2x1 gen() 7149 MB/s
[ 304.885373] raid6: sse2x1 xor() 6892 MB/s
[ 304.953370] raid6: sse2x2 gen() 11874 MB/s
[ 305.021366] raid6: sse2x2 xor() 8411 MB/s
[ 305.089361] raid6: sse2x4 gen() 13842 MB/s
[ 305.157356] raid6: sse2x4 xor() 10249 MB/s
[ 305.157357] raid6: using algorithm sse2x4 gen() 13842 MB/s
[ 305.157358] raid6: .... xor() 10249 MB/s, rmw enabled
[ 305.157359] raid6: using ssse3x2 recovery algorithm
[ 305.173207] xor: automatically using best checksumming function:
[ 305.209351] avx : 23160.000 MB/sec
[ 305.252714] Btrfs loaded
更新
以下是输出systemd-analyze blame
16.105s grub-common.service
15.804s [email protected]
14.856s ondemand.service
14.080s networking.service
14.057s apport.service
13.611s mysql.service
13.265s speech-dispatcher.service
12.494s irqbalance.service
10.698s sysstat.service
10.641s lightdm.service
7.857s dev-sda6.device
5.599s ModemManager.service
4.685s apparmor.service
4.666s accounts-daemon.service
3.626s NetworkManager.service
2.811s redis-server.service
2.670s systemd-logind.service
2.583s upower.service
2.506s gpu-manager.service
2.442s systemd-user-sessions.service
2.061s console-setup.service
1.994s thermald.service
1.756s systemd-tmpfiles-setup.service
1.726s setvtrgb.service
1.243s keyboard-setup.service
1.194s systemd-udevd.service
1.166s rsyslog.service
1.054s plymouth-start.service
1.026s systemd-tmpfiles-setup-dev.service
902ms colord.service
868ms avahi-daemon.service
614ms systemd-modules-load.service
578ms wpa_supplicant.service
555ms systemd-rfkill.service
537ms systemd-journald.service
420ms sys-kernel-debug.mount
420ms dev-mqueue.mount
419ms dev-hugepages.mount
348ms polkitd.service
345ms systemd-update-utmp.service
345ms systemd-timesyncd.service
337ms apt-daily.service
336ms systemd-sysctl.service
333ms dns-clean.service
311ms udisks2.service
310ms plymouth-read-write.service
301ms systemd-journal-flush.service
276ms ufw.service
276ms kmod-static-nodes.service
214ms systemd-udev-trigger.service
192ms resolvconf.service
132ms systemd-random-seed.service
126ms dev-disk-by\x2duuid-0b399021\x2dd995\x2d469b\x2d9027\x2d01183ad502e6.swap
100ms systemd-remount-fs.service
91ms pppd-dns.service
36ms snapd.socket
17ms [email protected]
8ms snapd.autoimport.service
7ms alsa-restore.service
3ms ureadahead-stop.service
3ms systemd-update-utmp-runlevel.service
2ms rtkit-daemon.service
2ms rc-local.service
1ms sys-fs-fuse-connections.mount
900us plymouth-quit-wait.service
670us postgresql.service
答案1
真正诊断问题的最佳方法是使用来自 的调用组合systemd-analyze。此工具不仅可以帮助您识别问题，还可以为您提供视觉表示。
执行如下所示的基本诊断。查看最普遍的项目并确定是否无法停止自动启动或修改某些配置
systemd-analyze blame 8.121s apt-daily.service 7.658s NetworkManager-wait-online.service 931ms docker.service 710ms winbind.service 695ms nmbd.service 647ms samba-ad-dc.service 543ms ModemManager.service如果上面的列表还不足以解释这一点，那么下一个最佳选择是使用绘图工具。这会将整个启动过程输出到 svg 文件中。是的，然后您就可以直观地看到问题了！您只需输入
systemd-analyze plot > test.svg打开 test.svg 并查看占用大量时间的各种服务。然后将它们从自动启动中删除，或者确定是否有可以进行配置来修复它们
重新启动计算机并再次运行步骤 2，查看是否还有其他问题