[v6] process scheduling (Niceness)
시간 할당을 더 덜 받도록 하여 cpu 사용 시간을 늘이는 설정
-20 ~ +19
기본 0
낮을수록 cpu 할당 많이 받음
renice 또는 top에서 변경가능
또는 시작시 지정
테스트용 프로세스 5개 생성
[root@server4 oshu]# cat /dev/zero > /dev/null &
[1] 27763
[root@server4 oshu]# cat /dev/zero > /dev/null &
[2] 27764
[root@server4 oshu]# cat /dev/zero > /dev/null &
[3] 27765
[root@server4 oshu]# cat /dev/zero > /dev/null &
[4] 27766
[root@server4 oshu]# cat /dev/zero > /dev/null &
[5] 27768
top으로 보니 생성한 프로세스가 약 20%씩 cpu를 사용하고 있음
[root@server4 oshu]# top
top - 01:24:33 up 6:53, 4 users, load average: 2.15, 0.55, 0.18
Tasks: 168 total, 6 running, 162 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.7%us, 96.3%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 503392k total, 456400k used, 46992k free, 11196k buffers
Swap: 557048k total, 22772k used, 534276k free, 145528k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27763 root 20 0 98.5m 548 440 R 20.3 0.1 0:37.38 cat
27765 root 20 0 98.5m 544 440 R 20.0 0.1 0:06.04 cat
27768 root 20 0 98.5m 544 440 R 20.0 0.1 0:05.25 cat
27764 root 20 0 98.5m 544 440 R 19.6 0.1 0:06.45 cat
27766 root 20 0 98.5m 548 440 R 19.6 0.1 0:05.83 cat
1 root 20 0 19232 880 668 S 0.0 0.2 0:00.64 init
2 root 20 0 0 0 0 S 0.0 0.0 0:00.00 kthreadd
특정 프로세스의 nice값을 수정 0->10으로 우선순위 밀리도록!
[root@server4 oshu]# renice -n 10 27766
27766: old priority 0, new priority 10
[root@server4 oshu]#
확인해보니 방금 nice값을 올린 프로세스 cpu 사용율 떨어짐
Tasks: 168 total, 6 running, 162 sleeping, 0 stopped, 0 zombie
Cpu(s): 4.0%us, 96.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 503392k total, 456532k used, 46860k free, 11224k buffers
Swap: 557048k total, 22772k used, 534276k free, 145540k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27765 root 20 0 98.5m 544 440 R 24.6 0.1 0:24.64 cat
27763 root 20 0 98.5m 548 440 R 24.2 0.1 0:55.97 cat
27764 root 20 0 98.5m 544 440 R 24.2 0.1 0:25.04 cat
27768 root 20 0 98.5m 544 440 R 24.2 0.1 0:23.85 cat
27766 root 30 10 98.5m 548 440 R 2.3 0.1 0:18.67 cat
다시 그놈을 nice 높임 10->-5
[root@server4 oshu]# renice -n -5 27766
27766: old priority 10, new priority -5
[root@server4 oshu]#
그놈 cpu 점유율이 가장 높아짐
top - 01:27:04 up 6:55, 4 users, load average: 4.76, 2.30, 0.89
Tasks: 168 total, 6 running, 162 sleeping, 0 stopped, 0 zombie
Cpu(s): 2.7%us, 97.3%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 503392k total, 456524k used, 46868k free, 11240k buffers
Swap: 557048k total, 22772k used, 534276k free, 145540k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27766 root 15 -5 98.5m 548 440 R 43.1 0.1 0:26.71 cat
27763 root 20 0 98.5m 548 440 R 14.2 0.1 1:09.77 cat
27765 root 20 0 98.5m 544 440 R 14.2 0.1 0:38.42 cat
27768 root 20 0 98.5m 544 440 R 14.2 0.1 0:37.64 cat
27764 root 20 0 98.5m 544 440 R 13.9 0.1 0:38.84 cat
27758 root 20 0 14940 1192 868 R 0.3 0.2 0:00.35 top
프로세스 하나를 더 생성함. 생성시 nice값을 지정했음 5
[root@server4 oshu]# nice -n 5 cat /dev/zero > /dev/null &
[6] 27784
nice값 5로 구동됨
Tasks: 169 total, 7 running, 162 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.0%us, 97.0%sy, 0.0%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 503392k total, 456664k used, 46728k free, 11252k buffers
Swap: 557048k total, 22772k used, 534276k free, 145572k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27766 root 15 -5 98.5m 548 440 R 41.1 0.1 0:56.25 cat
27763 root 20 0 98.5m 548 440 R 13.6 0.1 1:19.46 cat
27768 root 20 0 98.5m 544 440 R 13.6 0.1 0:47.35 cat
27764 root 20 0 98.5m 544 440 R 13.2 0.1 0:48.52 cat
27765 root 20 0 98.5m 544 440 R 13.2 0.1 0:48.11 cat
27784 root 25 5 98.5m 548 440 R 4.6 0.1 0:00.89 cat
1 root 20 0 19232 880 668 S 0.0 0.2 0:00.64 init
TOP에서 직접 nice값 변경 : 단축키 r
top - 01:28:54 up 6:57, 4 users, load average: 5.59, 3.31, 1.41
Tasks: 169 total, 7 running, 162 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.6%us, 96.0%sy, 0.3%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 503392k total, 456664k used, 46728k free, 11260k buffers
Swap: 557048k total, 22772k used, 534276k free, 145568k cached
PID to renice: 27766
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27766 root 15 -5 98.5m 548 440 R 41.4 0.1 1:13.10 cat
27763 root 20 0 98.5m 548 440 R 13.6 0.1 1:24.99 cat
27764 root 20 0 98.5m 544 440 R 13.6 0.1 0:54.06 cat
27765 root 20 0 98.5m 544 440 R 13.6 0.1 0:53.64 cat
27768 root 20 0 98.5m 544 440 R 13.6 0.1 0:52.87 cat
27784 root 25 5 98.5m 548 440 R 4.3 0.1 0:02.69 cat
1 root 20 0 19232 880 668 S 0.0 0.2 0:00.64 init
프로세스id를 입력하고 엔터, nice값을 입력하고 엔터
Renice PID 27766 to value: 15
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27766 root 15 -5 98.5m 548 440 R 41.4 0.1 1:13.10 cat
27763 root 20 0 98.5m 548 440 R 13.6 0.1 1:24.99 cat
27764 root 20 0 98.5m 544 440 R 13.6 0.1 0:54.06 cat
27765 root 20 0 98.5m 544 440 R 13.6 0.1 0:53.64 cat
27768 root 20 0 98.5m 544 440 R 13.6 0.1 0:52.87 cat
27784 root 25 5 98.5m 548 440 R 4.3 0.1 0:02.69 cat
renice됨 -5 -> 15로!
op - 01:30:01 up 6:58, 4 users, load average: 5.87, 3.87, 1.74
Tasks: 169 total, 7 running, 162 sleeping, 0 stopped, 0 zombie
Cpu(s): 3.7%us, 96.0%sy, 0.3%ni, 0.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 503392k total, 457192k used, 46200k free, 11280k buffers
Swap: 557048k total, 22772k used, 534276k free, 145564k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
27764 root 20 0 98.5m 544 440 R 22.9 0.1 1:03.77 cat
27763 root 20 0 98.5m 548 440 R 22.5 0.1 1:34.70 cat
27765 root 20 0 98.5m 544 440 R 22.5 0.1 1:03.35 cat
27768 root 20 0 98.5m 544 440 R 22.5 0.1 1:02.59 cat
27784 root 25 5 98.5m 548 440 R 7.6 0.1 0:05.87 cat
27766 root 35 15 98.5m 548 440 R 1.0 0.1 1:38.57 cat
테스트 마치고 cat 수행중인 프로세스 모두 kill
[root@server4 oshu]# killall cat