top - 21:15:43 up 2:28, 1 user, load average: 0.54, 0.50, 0.52
Tasks: 225 total, 1 running, 223 sleeping, 0 stopped, 1 zombie
Cpu(s): 0.4%us, 2.9%sy, 0.0%ni, 96.5%id, 0.2%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 8181868k total, 4332744k used, 3849124k free, 1336596k buffers
Swap: 15624184k total, 0k used, 15624184k free, 169468k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
85 root 25 5 0 0 0 S 17 0.0 28:57.08 ksmd
2457 root 20 0 1232m 922m 3404 S 3 11.6 14:37.69 kvm
2431 root 20 0 2270m 1.1g 3392 S 2 14.0 7:01.86 kvm
2344 root 20 0 1981m 324m 3392 S 1 4.1 0:46.49 kvm
3911 root 20 0 2249m 320m 3364 S 1 4.0 1:57.91 kvm
10636 root 20 0 19332 1504 1056 R 0 0.0 0:00.07 top
10871 root 20 0 54732 2472 1788 S 0 0.0 0:00.01 apache2
1 root 20 0 23944 2220 1292 S 0 0.0 0:14.87 init
2 root 20 0 0 0 0 S 0 0.0 0:00.02 kthreadd
3 root RT 0 0 0 0 S 0 0.0 0:00.01 migration/0
4 root 20 0 0 0 0 S 0 0.0 0:00.10 ksoftirqd/0
5 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/0
6 root RT 0 0 0 0 S 0 0.0 0:00.01 migration/1
7 root 20 0 0 0 0 S 0 0.0 0:00.51 ksoftirqd/1
8 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/1
9 root RT 0 0 0 0 S 0 0.0 0:00.03 migration/2
10 root 20 0 0 0 0 S 0 0.0 0:00.45 ksoftirqd/2
11 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/2
12 root RT 0 0 0 0 S 0 0.0 0:00.01 migration/3
13 root 20 0 0 0 0 S 0 0.0 0:00.81 ksoftirqd/3
14 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/3
15 root RT 0 0 0 0 S 0 0.0 0:00.14 migration/4
16 root 20 0 0 0 0 S 0 0.0 0:00.13 ksoftirqd/4
17 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/4
18 root RT 0 0 0 0 S 0 0.0 0:00.15 migration/5
19 root 20 0 0 0 0 S 0 0.0 0:00.15 ksoftirqd/5
20 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/5
21 root RT 0 0 0 0 S 0 0.0 0:00.07 migration/6
22 root 20 0 0 0 0 S 0 0.0 0:00.05 ksoftirqd/6
23 root RT 0 0 0 0 S 0 0.0 0:00.00 watchdog/6
24 root RT 0 0 0 0 S 0 0.0 0:00.19 migration/7
25 root 20 0 0 0 0 S 0 0.0 0:00.29 ksoftirqd/7
上面是我在执行 a 时服务器上的 top 输出top，我发现服务器对按键的响应非常慢。例如，我virt-manager在命令提示符下键入，我可以看到当我按下任意键时，响应都会在相当长的延迟后出现。上述情况可能是什么原因造成的，我应该检查什么？