Introduction

It is often easy and often large to graph the data acquired on a regular basis. However, I think that the hurdles are high for inexperienced people, so I hope to provide an entrance. (The rest is python mission)

Graphing meminfo

As an example, let's easily graph the information of / proc / meminfo acquired regularly with shell and python.

It is assumed that the meminfo information is saved in the format <date> / <hour, minute, second> /meminfo.log (example: 20160224/105312 / meminfo.log).

The format of meminfo looks like this

MemTotal:         511476 kB
MemFree:          269240 kB
Buffers:           13936 kB
Cached:            56044 kB
SwapCached:            0 kB
Active:            36944 kB
Inactive:          47324 kB
Active(anon):      14648 kB
Inactive(anon):      208 kB
Active(file):      22296 kB
Inactive(file):    47116 kB
Unevictable:           0 kB
Mlocked:               0 kB
HighTotal:             0 kB
HighFree:              0 kB
LowTotal:         511476 kB
LowFree:          269240 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:         14304 kB
Mapped:            16548 kB
Shmem:               568 kB
Slab:               7416 kB
SReclaimable:       2600 kB
SUnreclaim:         4816 kB
KernelStack:         504 kB
PageTables:          784 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:      255736 kB
Committed_AS:     195212 kB
VmallocTotal:    1548288 kB
VmallocUsed:        8428 kB
VmallocChunk:    1350896 kB

Suppose you want to graph the value of Committed_AS in meminfo

$ find . -name 'meminfo.log' | sort | xargs grep Committed_AS

Then, the following output is obtained.

./20160211/190409/meminfo.log:Committed_AS:     389260 kB
./20160211/191528/meminfo.log:Committed_AS:     389300 kB
./20160211/192648/meminfo.log:Committed_AS:     394600 kB

This is further processed by gawk into the date number format.

$ find . -name 'meminfo.log' | sort | xargs grep Committed_AS | gawk 'match($0, /\/([0-9]+)\/([0-9]+).*[0-9]+ kB/, a) {print a[1] a[2], $2}'

20160211190409 389260
20160211191528 389300
20160211192648 394600

Then draw this with matplot

`plot_date.py`


#!/usr/bin/env python3 

import matplotlib.pyplot as plt

from datetime import datetime as dt

import sys

[date, y] = zip(*[l.split() for l in sys.stdin])
date=[dt.strptime(d, "%Y%m%d%H%M%S") for d in date]

plt.plot(date,y)

plt.show()

$ find . -name 'meminfo.log' | sort | xargs grep Committed_AS | gawk 'match($0, /\/([0-9]+)\/([0-9]+).*[0-9]+ kB/, a) {print a[1] a[2], $2}' | python3 plot_date.py