我听说 Ubuntu 可以在 30 秒左右启动，但我每次启动 Ubuntu 都要花 60 多秒。我还看到一些论坛说需要发布 dmesg 和 bootchart 来确定哪个进程减慢了启动时间，因为我不是 Ubuntu 专家，希望了解更多，我谦虚地请这里的任何专业人士教我如何操作。
我的笔记本电脑规格：
Model : ASUS K45VS
RAM : 8MB
CPU : Intel(R) Core(TM) i7-3630QM CPU @ 2.40GHz x 8
Graphic Card : nVidia GeForce GT 645M
HDD : 750GB
OS : Single boot Ubuntu 12.04LTS
System.uname : Linux 3.8.0-39-generic #58~precise1-Ubuntu SMP Fri May 2 21:33:40 UTC 2014 x86_64
System.release : Ubuntu 12.04.4 LTS
System.kernel.options : BOOT_IMAGE=/boot/vmlinuz-3.8.0-39-generic root=UUID=c8a71503-bce8-406c-9a5f-5aa8284f5c7c ro quiet splash
我的 dmesg（突出显示了巨大的时间范围差距）：
[ 30.772656] cgroup: libvirtd (1961) created nested cgroup for controller "memory" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.
[ 30.772659] cgroup: "memory" requires setting use_hierarchy to 1 on the root.
[ 30.772683] cgroup: libvirtd (1961) created nested cgroup for controller "devices" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.
[ 30.772710] cgroup: libvirtd (1961) created nested cgroup for controller "blkio" which has incomplete hierarchy support. Nested cgroups may change behavior in the future.
[ 32.140335] nvidia 0000:01:00.0: irq 46 for MSI/MSI-X
[ 32.505619] ACPI Error: Field [TMPB] at 1081344 exceeds Buffer [ROM1] size 262144 (bits) (20121018/dsopcode-236)
[ 32.505624] ACPI Error: Method parse/execution failed [\_SB_.PCI0.PEG0.PEGP._ROM] (Node ffff880224e91f00), AE_AML_BUFFER_LIMIT (20121018/psparse-537)
[ 802.034422] audit_printk_skb: 69 callbacks suppressed
[ 802.034428] type=1400 audit(1400914804.392:35): apparmor="DENIED" operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=1683 comm="cupsd" pid=1683 comm="cupsd" capability=36 capname="block_suspend"
[ 1581.300901] type=1400 audit(1400915584.816:36): apparmor="DENIED" operation="capable" parent=1 profile="/usr/sbin/cupsd" pid=1683 comm="cupsd" pid=1683 comm="cupsd" capability=36 capname="block_suspend"
我的 Bootchart.png：
希望能够学习提高我的启动时间和知识。提前谢谢 :)