Why I fail so bad to check for memory leak with this code?

[Marco Sulla]

I've done this other simple test:

#!/usr/bin/env python3

import tracemalloc
import gc
import pickle

tracemalloc.start()

snapshot1 = tracemalloc.take_snapshot().filter_traces(
    (tracemalloc.Filter(True, __file__), )
)

for i in range(10000000):
    pickle.dumps(iter([]))

gc.collect()

snapshot2 = tracemalloc.take_snapshot().filter_traces(
    (tracemalloc.Filter(True, __file__), )
)

top_stats = snapshot2.compare_to(snapshot1, 'lineno')
tracemalloc.stop()

for stat in top_stats:
    print(stat)

The result is:

/home/marco/sources/test.py:14: size=3339 B (+3339 B), count=63 (+63),
average=53 B
/home/marco/sources/test.py:9: size=464 B (+464 B), count=1 (+1),
average=464 B
/home/marco/sources/test.py:10: size=456 B (+456 B), count=1 (+1),
average=456 B
/home/marco/sources/test.py:13: size=28 B (+28 B), count=1 (+1), average=28
B

It seems that, after 10 million loops, only 63 have a leak, with only ~3
KB. It seems to me that we can't call it a leak, no? Probably pickle needs
a lot more cycles to be sure there's actually a real leakage.