HW4 : CPU bound vs. IO bound

1.What is CPU bound and IO bound process?

A : CPU-bound(計算密集型)
在多重程式系統中，大部份時間用來做計算、邏輯判斷等CPU動作的程式稱之 CPU bound。例如一個計算圓周率至小數點一千位以下的程式，在執行的過程當中
絕大部份時間用在三角函式和開根號的計算，便是屬於CPU bound的程式。
I/O密集型 (CPU-bound)
I/O bound 指的是系統的CPU效能相對硬碟/記憶體的效能要好很多，此時，系統運作，大部分的狀況是 CPU 在等 I/O (硬碟/記憶體) 的讀/寫，此時 CPU Loading 不高。
CPU bound 指的是系統的 硬碟/記憶體 效能 相對 CPU 的效能 要好很多，此時，系統運作，大部分的狀況是 CPU Loading 100%，CPU 要讀/寫 I/O (硬碟/記憶體)，I/O在很短的時間就可以完成，而 CPU 還有許多運算要處理，CPU Loading 很高。

2.Use stress tool to make you own examples:
Demo and explain your example in vmstat, iostat or other commands

家用電腦輸入那些指令無法查得。

CPU and memory stress tests

#sudo stress -m 1 --vm-bytes 1.5G
stress: info: [4407] dispatching hogs: 0 cpu, 0 io, 1 vm, 0 hdd

#free
total used free shared buffers cached
Mem: 2032348 1315096 717252 16588 40468 208136
-/+ buffers/cache: 1066492 965856
Swap: 2094076 117108 1976968

#top
top - 01:31:38 up 16 min, 3 users, load average: 0.89, 0.64, 0.43
Tasks: 226 total, 2 running, 222 sleeping, 2 stopped, 0 zombie
%Cpu(s): 11.0 us, 89.0 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 2032348 total, 1266956 used, 765392 free, 36488 buffers
KiB Swap: 2094076 total, 117104 used, 1976972 free. 208140 cached Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
4408 root 20 0 1055904 381424 784 R 95.1 18.8 0:19.78 stress

#sar 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

01:32:37 AM CPU %user %nice %system %iowait %steal %idle
01:32:38 AM all 12.00 0.00 88.00 0.00 0.00 0.00
01:32:39 AM all 5.00 0.00 95.00 0.00 0.00 0.00

#mpstat 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

01:33:18 AM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle
01:33:19 AM all 9.00 0.00 91.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

IO stress test

Example: 30 IO sync threads

#stress --io 30
stress: info: [4435] dispatching hogs: 0 cpu, 30 io, 0 vm, 0 hdd

#iostat -kx 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
6.10 2.42 36.27 4.48 0.00 50.74

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 1.38 30.35 47.83 5.99 769.71 403.65 43.60 0.73 13.48 11.39 30.25 1.24 6.68

Example: 1 thread to write disk (default: 1 GB)

#stress -d 1
stress: info: [4508] dispatching hogs: 0 cpu, 0 io, 0 vm, 1 hdd

#iostat -kx 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
5.75 2.23 40.08 4.54 0.00 47.40

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 1.27 29.45 44.12 6.37 709.68 1313.17 80.14 0.80 15.82 11.45 46.08 1.38 6.96

#vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
4 0 117032 1070944 34944 314440 2 92 707 1915 340 829 8 40 47 5 0
3 1 117032 982840 34948 400272 0 0 0 93700 136 485 3 15 0 82 0

CPU and memory stress tests

#stress -m 1 --vm-bytes 1.5G
stress: info: [4685] dispatching hogs: 0 cpu, 0 io, 1 vm, 0 hdd

#free
total used free shared buffers cached
Mem: 2032348 1470364 561984 16588 39588 217008
-/+ buffers/cache: 1213768 818580
Swap: 2094076 116624 1977452

#top
top - 02:24:50 up 1:09, 3 users, load average: 0.61, 0.18, 0.27
Tasks: 225 total, 2 running, 221 sleeping, 2 stopped, 0 zombie
%Cpu(s): 9.7 us, 90.3 sy, 0.0 ni, 0.0 id, 0.0 wa, 0.0 hi, 0.0 si, 0.0 st
KiB Mem: 2032348 total, 1908908 used, 123440 free, 39636 buffers
KiB Swap: 2094076 total, 116620 used, 1977456 free. 217012 cached Mem

PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
4686 root 20 0 1055904 0.990g 688 R 96.4 51.1 0:37.68 stress

#sar 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

02:26:46 AM CPU %user %nice %system %iowait %steal %idle
02:26:47 AM all 7.92 0.00 92.08 0.00 0.00 0.00
02:26:48 AM all 7.00 0.00 93.00 0.00 0.00 0.00

#mpstat 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

02:26:54 AM CPU %usr %nice %sys %iowait %irq %soft %steal %guest %gnice %idle
02:26:55 AM all 10.00 0.00 90.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00
02:26:56 AM all 10.00 0.00 90.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00

IO stress test
Example: 30 IO sync threads

#stress --io 30
stress: info: [4708] dispatching hogs: 0 cpu, 30 io, 0 vm, 0 hdd

#iostat -kx 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
2.23 0.67 13.92 1.54 0.00 81.63

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 0.40 9.69 13.40 2.43 215.13 734.19 119.96 0.29 18.14 11.42 55.28 1.56 2.47

Example: 1 thread to write disk (default: 1 GB)

#stress -d 1
stress: info: [4759] dispatching hogs: 0 cpu, 0 io, 0 vm, 1 hdd

#iostat -kx 1
Linux 3.19.0-80-generic (ubuntu) 11/04/2019 _x86_64_ (1 CPU)

avg-cpu: %user %nice %system %iowait %steal %idle
2.23 0.66 14.90 1.65 0.00 80.56

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 0.39 9.98 13.20 2.59 211.86 995.03 152.90 0.33 20.74 11.42 68.24 1.66 2.62

#vmstat 1
procs -----------memory---------- ---swap-- -----io---- -system-- ------cpu-----
r b swpd free buff cache si so bi bo in cs us sy id wa st
0 1 116312 1046888 40696 328304 1 27 212 1196 227 533 3 15 80 2 0
0 1 116312 851648 40696 518548 0 0 0 184324 457 1512 1 6 0 93 0