High CPU Usage on RedHat 7.8
Symptoms
ksoftirqd/0 High CPU.
Tasks: 254 total, 2 running, 252 sleeping, 0 stopped, 0 zombie
%Cpu(s): 0.4 us, 6.2 sy, 0.0 ni, 0.8 id, 57.3 wa, 0.0 hi, 35.2 si, 0.0 st
KiB Mem : 995712 total, 73416 free, 804532 used, 117764 buff/cache
KiB Swap: 2097148 total, 1847020 free, 250128 used. 25080 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
6 root 20 0 0 0 0 R 94.7 0.0 11:37.23 ksoftirqd/0
5063 oracle -2 0 993672 1324 1224 S 13.7 0.1 2:28.50 oracle
24 root 20 0 0 0 0 S 10.9 0.0 1:32.94 ksoftirqd/3
46 root 20 0 0 0 0 S 7.8 0.0 1:42.71 kswapd0
19 root 20 0 0 0 0 S 7.2 0.0 1:19.65 ksoftirqd/2
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Cause
Insufficient memory space, as the database starts, the CPU usage rate rises and the number of soft interrupts increases.
~]# iostat -x 1
avg-cpu: %user %nice %system %iowait %steal %idle
0.49 0.00 32.60 57.91 0.00 9.00
Device: rrqm/s wrqm/s r/s w/s rkB/s wkB/s avgrq-sz avgqu-sz await r_await w_await svctm %util
sda 80.00 3.00 5376.00 9.00 124208.00 48.00 46.15 151.71 28.25 28.27 12.11 0.20 106.00
dm-0 0.00 0.00 5420.00 7.00 123568.00 28.00 45.55 157.43 29.10 29.12 11.71 0.20 106.00
dm-1 0.00 0.00 7.00 5.00 28.00 20.00 8.00 0.70 68.58 109.57 11.20 26.08 31.30
sdb 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdc 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
dm-2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
dm-3 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
~]# lsscsi -s
[0:0:0:0] disk VMware, VMware Virtual S 1.0 /dev/sda 53.6GB
[4:0:0:0] cd/dvd NECVMWar VMware SATA CD01 1.00 /dev/sr0 -
[34:0:0:0] disk LIO-ORG pcs_data_1 4.0 /dev/sdb 5.36GB
[34:0:0:1] disk LIO-ORG pcs_arch_1 4.0 /dev/sdc 1.07GB
~]$ free -m
total used free shared buff/cache available
Mem: 972 775 75 34 121 44
Swap: 2047 132 1915
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Solution
Increate memory.
