cloud-init-dev team mailing list archive

[Ryan Harper <ryan.harper@xxxxxxxxxxxxx>]

> - use arrays for each 'section' rather than content += . This allows better
>   separation of the sections and also will perform better as long strings
>   with += are slow.


+1 for better separation.  I don't think there is significant difference:

For an 100-line eni (that's rather high for typical usage)

% python3 t.py 
Concat: 7.116918564017396
Array : 7.6817819369607605

% python2 t.py 
Generating data...
Concat: 8.51635122299
Array : 7.93058490753

For a 10-line eni

% python3 t.py 
Generating data...
Concat: 1.0464658139972016
Array : 1.2140009650029242

% python2 t.py 
Generating data...
Concat: 0.956037998199
Array : 1.08836984634

% cat t.py
import timeit

concat = """
c=''
for x in range(0, 100):
    c += 'iface eth0 inet static'
"""

append = """
c = []
for x in range(0, 100):
	c.append('iface eth0 inet static')
"""

print('Generating data...')
print("Concat: %s" % timeit.timeit(concat))
print("Array : %s" % timeit.timeit(append))

-- 
https://code.launchpad.net/~smoser/cloud-init/trunk.net-improve-lo-dns/+merge/298035
Your team cloud init development team is requested to review the proposed merge of lp:~smoser/cloud-init/trunk.net-improve-lo-dns into lp:cloud-init.