1.4.0rc1: Python-level memory "leak" (internal font cache?)

[letmaik]

I'm currently testing the 1.4.0rc1 (had to change the min_version of freetype2 to 1.3, see #3262). It seems that the memory leak reported in #3197 is gone, but I still see a very slow but considerable increase in resident memory, and in fact I can observe a constant Python object count growth of the following classes:

__builtin__.list 14645  +114
__builtin__.dict    18076   +114
matplotlib.font_manager.FontProperties  761 +114

(measured using objgraph)

So I think between 1.3.1 and 1.4.0rc1 some kind of new "leak" appeared on Python level. It's not a real leak as the objects are accessible, so I guess it's a kind of internal font (property) cache which doesn't clear up old entries.

Test script:

import numpy as np
import matplotlib as mpl
mpl.use('agg')
import matplotlib.pyplot as plt

for i in range(100000):
    fig, ax = plt.subplots()         

    circle1=plt.Circle((0,0),2,color='r',rasterized=True)
    ax.add_artist(circle1)

    fig.savefig('test.svg')
    plt.close(fig)

EDIT: I had measured object count growth for 1.3.1 also, and there was no growth of any class there.

[WeatherGod]

I think this is a fantastic example of the "many eyes" situation in
software development. We have been so focused on finding actual leaks using
valgrind that we didn't really think to see if there were any other
increases in memory usage. This is certainly a very interesting result.
Thank you (and thanks for mentioning objgraph, I never heard of it and it
looks useful).

On Tue, Jul 15, 2014 at 10:45 AM, Maik Riechert notifications@github.com
wrote:

I'm currently testing the 1.4.0rc1 (had to change the min_version of
freetype2 to 1.3, see #3262
#3262). It seems that
the memory leak reported in #3197
#3197 is gone, but I
still see a very slow but considerable increase in resident memory, and in
fact I can observe a constant object count growth of the following classes:

builtin.list 14645 +114
builtin.dict 18076 +114
matplotlib.font_manager.FontProperties 761 +114

(measured using objgraph)

So I think between 1.3.1 and 1.4.0rc1 some kind of new "leak" appeared on
Python level. It's not a real leak as the objects are accessible, so I
guess it's a kind of internal font (property) cache which doesn't clear up
old entries.

Test script:

import numpy as npimport matplotlib as mplmpl.use('agg')import matplotlib.pyplot as plt
for i in range(100000):
fig, ax = plt.subplots()

circle1=plt.Circle((0,0),2,color='r',rasterized=True)
ax.add_artist(circle1)

fig.savefig('test.svg')
plt.close(fig)

—
Reply to this email directly or view it on GitHub
#3264.

[tacaswell]

This is probably related to the change to re-setting the font-cache (#3077).