我正在运行 Kubuntu 18.04。启动大约需要 90 秒，这比它应该的时间长得多。如果我运行，dmesg有两个明显的“跳跃”。第一个是：
[ 2.876292] clocksource: Switched to clocksource tsc
[ 34.123020] EXT4-fs (sdb5): mounted filesystem with ordered data mode. Opts: (null)
sdb5 是我的启动驱动器；一个 ssd。fdisk -l输出是
Device Boot Start End Sectors Size Id Type
/dev/sdb3 2048 250068991 250066944 119.2G 5 Extended
/dev/sdb5 4096 250068991 250064896 119.2G 83 Linux
不太确定为什么挂载该文件系统需要这么长时间 - 这是我的第一个问题 - 我如何诊断挂载该磁盘的问题？
第二次时间跳跃如下：
[ 39.440877] virbr0: port 1(virbr0-nic) entered disabled state
[ 83.788740] Could not find key with description: [391e121390deac97]
[ 83.788743] process_request_key_err: No key
[ 83.788744] Could not find valid key in user session keyring for sig specified in mount option: [391e121390deac97]
[ 83.788745] One or more global auth toks could not properly register; rc = [-2]
[ 83.788746] Error parsing options; rc = [-2]
我认为这与安装加密目录有关；对吗？如果是这样，那可能是 KDE 等离子保险库损坏了，因为我的主目录没有加密，所以我会把那个保险库扔掉。
编辑：输出为systemd-analyze critical-chain：
The time after the unit is active or started is printed after the "@" character.
The time the unit takes to start is printed after the "+" character.
graphical.target @4.648s
└─multi-user.target @4.648s
└─kerneloops.service @4.638s +9ms
└─network-online.target @4.637s
└─NetworkManager-wait-online.service @2.464s +2.172s
└─NetworkManager.service @2.136s +326ms
└─dbus.service @2.070s
└─basic.target @2.065s
└─sockets.target @2.065s
└─snapd.socket @2.059s +5ms
└─sysinit.target @2.059s
└─systemd-timesyncd.service @1.935s +123ms
└─systemd-tmpfiles-setup.service @1.917s +16ms
└─local-fs.target @1.913s
└─home-djrscally.mount @14.042s
└─local-fs-pre.target @270ms
└─keyboard-setup.service @177ms +93ms
└─systemd-journald.socket @169ms
└─system.slice @168ms
└─-.slice @167ms
并且systemd-analyze blame是：
8.653s apt-daily.service
2.338s apt-daily-upgrade.service
2.172s NetworkManager-wait-online.service
1.370s dev-sdb5.device
1.285s mariadb.service
8.653s apt-daily.service
2.338s apt-daily-upgrade.service
2.172s NetworkManager-wait-online.service
1.370s dev-sdb5.device
这是每条超过一秒的记录