系统长引导

Question

我有一个戴尔纬度6440 -intel i5-4310笔记本电脑，8GB内存磁盘- SSD。系统上的SD卡- Ubuntu 18.04.3内核5.2.8。加密的分区/主页。

这就是系统分析的样子：

Startup finished in
   8.807s (firmware) + 30.926s (loader)  
 + 3.776s (kernel)   + 32.108s (userspace)  
= 1min 15.618s  

graphical.target reached after 32.101s in userspace

它负责什么，加载程序是什么？如何加快速度？

$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 @14.312s  
└─lightdm.service @12.694s +1.617s  
  └─systemd-user-sessions.service @12.671s +13ms  
    └─network.target @12.670s  
      └─NetworkManager.service @10.163s +2.505s  
        └─dbus.service @9.653s  
          └─basic.target @9.641s  
            └─sockets.target @9.641s  
              └─dbus.socket @9.638s  
                └─sysinit.target @9.623s  
                  └─apparmor.service @9.423s +198ms  
                    └─local-fs.target @9.420s  
                      └─home-groszek-.cache.mount @9.416s +3ms  
                        └─home.mount @9.386s +16ms  
                          └─systemd-fsck@dev-mapper-mmcblk0p8_crypt.service @9.3  
                            └─dev-mapper-mmcblk0p8_crypt.device @9.365s  

$ lsblk
NAME                MAJ:MIN RM   SIZE RO TYPE  MOUNTPOINT
loop0                 7:0    0  71,7M  1 loop  /snap/software-boutique/31
loop1                 7:1    0    16K  1 loop  /snap/software-boutique/39
loop2                 7:2    0  88,7M  1 loop  /snap/core/7396
loop3                 7:3    0  88,5M  1 loop  /snap/core/7270
loop4                 7:4    0   7,9M  1 loop  /snap/pulsemixer/23
loop5                 7:5    0   7,9M  1 loop  /snap/pulsemixer/250
loop6                 7:6    0  87,3M  1 loop  /snap/ubuntu-mate-welcome/220
loop7                 7:7    0  86,3M  1 loop  /snap/ubuntu-mate-welcome/335
sda                   8:0    0 298,1G  0 disk  
├─sda1                8:1    0  39,2M  0 part  
├─sda2                8:2    0  13,8G  0 part  
├─sda3                8:3    0 226,3G  0 part  /media/OS
└─sda4                8:4    0    58G  0 part  
sr0                  11:0    1  1024M  0 rom   
mmcblk0             179:0    0  59,5G  0 disk  
├─mmcblk0p1         179:1    0   285M  0 part  /boot/efi
├─mmcblk0p2         179:2    0     1K  0 part  
├─mmcblk0p5         179:5    0   6,1G  0 part  /
├─mmcblk0p6         179:6    0  15,9G  0 part  /usr
├─mmcblk0p7         179:7    0   6,1G  0 part  /var
└─mmcblk0p8         259:0    0  31,3G  0 part  
  └─mmcblk0p8_crypt 25If you know how to solve this, please leave your comment, I really appreciate it!3:0    0  31,3G  0 crypt /home
zram0               252:0    0   985M  0 disk  [SWAP]
zram1               252:1    0   985M  0 disk  [SWAP]
zram2               252:2    0   985M  0 disk  [SWAP]
zram3               252:3    0   985M  0 disk  [SWAP]

$ sudo hdparm -tT /dev/mmcblk0
/dev/mmcblk0:
 Timing cached reads:   13722 MB in  2.00 seconds = 6873.86 MB/sec
 Timing buffered disk reads:  70 MB in  3.08 seconds =  22.74 MB/sec

Answer 1

使用hdparm的基准测试给出了非常慢的读取速率

$sudo hdparm -tT /dev/mmcblk0 0.定时缓冲磁盘读取: 70 MB，3.08秒=22.74MB/秒

所以这22 MB/秒是一个瓶颈。还要考虑的是，这是顺序读取速度，而实际速度与随机访问可能甚至更慢。加密也可能降低速度。内部HDD目前的等级为150 MB/s，而SSD为>500 MB/s。

考虑使用以下选项之一：

• 购买更快的SD卡与10级和UHS I(或UHS III)评级-例如三星PRO或PRO +；
• 购买快速USB闪存-例如ADATA，UE700或；
• 购买2.5“SATA / mSATA / M.2 SSD (我不完全了解您的笔记本电脑的内部结构)，容量约512 GB，并在Windows分区之后将Ubuntu移动到它。