Hello Timothy,
we have 24 CPUs and from time to time some of them get wait states just for a second. I had to wait for some 10-30 seconds to get the following output. The next top refresh shows already 0.x % wait states for this CPUs.
top - 19:47:49 up 19 days, 10:33, 1 user, load average: 16.41, 18.07, 18.15
Tasks: 726 total, 10 running, 714 sleeping, 0 stopped, 2 zombie
Cpu0 : 51.1%us, 8.5%sy, 0.0%ni, 23.1%id, 11.1%wa, 0.0%hi, 6.2%si, 0.0%st
Cpu1 : 31.2%us, 5.5%sy, 1.0%ni, 62.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu2 : 29.2%us, 6.2%sy, 1.3%ni, 63.3%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu3 : 28.2%us, 5.5%sy, 5.8%ni, 60.2%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu4 : 51.1%us, 10.4%sy, 0.0%ni, 31.9%id, 6.5%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu5 : 81.6%us, 8.4%sy, 0.0%ni, 10.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu6 : 51.8%us, 4.9%sy, 0.3%ni, 43.0%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu7 : 29.1%us, 3.9%sy, 4.6%ni, 62.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu8 : 44.8%us, 3.6%sy, 0.3%ni, 50.6%id, 0.3%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu9 : 28.7%us, 3.6%sy, 0.7%ni, 66.8%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu10 : 32.0%us, 5.5%sy, 1.9%ni, 60.2%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu11 : 62.0%us, 6.8%sy, 2.3%ni, 28.6%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu12 : 42.7%us, 5.8%sy, 0.6%ni, 35.0%id, 15.5%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu13 : 43.4%us, 9.7%sy, 0.0%ni, 46.9%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu14 : 46.4%us, 5.5%sy, 0.6%ni, 45.8%id, 1.6%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu15 : 31.6%us, 5.2%sy, 4.9%ni, 58.0%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu16 : 36.9%us, 4.5%sy, 0.3%ni, 57.3%id, 1.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu17 : 51.5%us, 27.2%sy, 0.3%ni, 20.7%id, 0.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu18 : 43.3%us, 5.9%sy, 1.6%ni, 48.9%id, 0.3%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu19 : 59.4%us, 5.2%sy, 1.3%ni, 33.1%id, 1.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu20 : 71.8%us, 6.5%sy, 0.6%ni, 19.7%id, 1.0%wa, 0.0%hi, 0.3%si, 0.0%st
Cpu21 : 32.8%us, 8.1%sy, 0.6%ni, 58.4%id, 0.0%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu22 : 30.4%us, 3.6%sy, 0.3%ni, 38.2%id, 27.5%wa, 0.0%hi, 0.0%si, 0.0%st
Cpu23 : 45.8%us, 13.3%sy, 0.3%ni, 40.3%id, 0.3%wa, 0.0%hi, 0.0%si, 0.0%st
Mem: 131868088k total, 130985980k used, 882108k free, 3141268k buffers
Swap: 67103496k total, 28332k used, 67075164k free, 64537056k cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
25868 admin 18 0 5732m 1.4g 12m S 199 1.1 2407:30 java
5719 admin 21 0 7896m 1.3g 450m S 104 1.0 2058:32 java
4379 admin 25 0 1040m 707m 48m R 97 0.5 226:22.75 fwm
24215 admin 25 0 865m 533m 49m R 94 0.4 197:02.74 fwm
13797 cp_postg 18 0 1667m 1.6g 1.5g R 88 1.3 104:00.13 postgres
13776 cp_postg 18 0 1606m 1.5g 1.5g R 85 1.2 618:29.11 postgres
24246 admin 18 0 680m 357m 46m R 62 0.3 120:20.54 fwm
26016 admin 18 0 1585m 734m 13m S 35 0.6 1152:20 java
4595 admin 16 0 890m 566m 48m R 34 0.4 259:16.34 fwm
4717 admin 15 0 709m 395m 47m S 33 0.3 141:22.46 fwm
24299 admin 15 0 911m 595m 48m S 29 0.5 195:31.70 fwm
Here some I/O statistics (taken every second):
(the first output listed here is not the first output of that command - so you can trust the values 🙂 )
avg-cpu: %user %nice %system %iowait %steal %idle
29.86 0.71 2.29 0.29 0.00 66.85
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 779.21 0.00 732.67 0.00 12095.05 16.51 0.28 0.38 0.07 4.95
sdb 0.00 0.00 0.00 891.09 0.00 23706.93 26.60 0.92 1.04 0.06 5.25
dm-0 0.00 0.00 0.00 0.00 0.00 12380.20 0.00 0.46 0.00 0.00 5.15
dm-1 0.00 0.00 0.00 2927.72 0.00 23421.78 8.00 5.34 1.83 0.02 5.54
avg-cpu: %user %nice %system %iowait %steal %idle
22.48 1.46 3.75 0.25 0.00 72.06
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
dm-0 0.00 0.00 1.00 0.00 16.00 7368.00 7384.00 0.28 282.00 39.00 3.90
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
avg-cpu: %user %nice %system %iowait %steal %idle
30.13 0.67 5.49 0.17 0.00 63.55
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
sdb 0.00 0.00 0.00 807.92 0.00 13306.93 16.47 0.68 0.85 0.05 3.76
dm-0 0.00 0.00 0.00 0.00 0.00 13306.93 0.00 1.16 0.00 0.00 3.76
dm-1 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
avg-cpu: %user %nice %system %iowait %steal %idle
29.67 2.46 3.87 0.33 0.00 63.67
Device: rrqm/s wrqm/s r/s w/s rsec/s wsec/s avgrq-sz avgqu-sz await svctm %util
sda 0.00 1455.45 0.00 636.63 0.00 16736.63 26.29 2.19 3.43 0.04 2.67
sdb 0.00 0.00 0.00 629.70 0.00 14217.82 22.58 0.95 1.50 0.08 4.95
dm-0 0.00 0.00 0.00 0.00 0.00 10336.63 0.00 0.60 0.00 0.00 4.75
dm-1 0.00 0.00 0.00 2577.23 0.00 20617.82 8.00 9.47 3.67 0.01 2.67