升级到 15.04 后，一台计算机的启动速度非常非常慢 - 几分钟，而不是大约 20 秒。
我不知道这是否有帮助：
graphical.target @1min 40.961s
??multi-user.target @1min 40.961s
??kerneloops.service @1min 36.392s +16ms
??network-online.target @1min 36.391s
??network.target @1min 30.948s
??wpa_supplicant.service @1min 31.430s +6ms
??basic.target @1min 30.414s
??sockets.target @1min 30.414s
??acpid.socket @1min 30.414s
??sysinit.target @1min 30.412s
??networking.service @1.941s +49ms
??apparmor.service @1.383s +555ms
??local-fs.target @1.381s
??media-andre-6564\x2d3236.mount @2min 17.386s
??local-fs-pre.target @1.375s
??systemd-remount-fs.service @1.328s +41ms
??systemd-fsck-root.service @1.197s +129ms
??system.slice @324ms
??-.slice @323ms
andre@andre-Latitude-E5520:~$ systemd
Failed to create root cgroup hierarchy: Permission denied
Failed to allocate manager object: Permission denied