Ho uno script molto semplice che alloca la memoria, dels
l'unico riferimento a un oggetto di dimensioni considerevoli, mentre stampa i report heapy
e pidstat
. Dopo aver eseguito lo script, Heapy mi dice che non ci dovrebbe essere molta memoria utilizzata mentre pidstat mi dice il contrario:python - la memoria non viene restituita al kernel
from guppy import hpy
import time
import sys
import os
'''
1) print heapy and pidstat report after starting and before actually doing any work
2) allocate some memory in a simple 2d array
3) print heapy and pidstat report
4) del the d2 array (attempt at garbage collection)
5) print heapy and pidstat report
6) sleep so pidstat can continue to be run to check on memory
'''
def pidstat(msg):
print '==============================='
print msg
os.system('pidstat -r -p %s' % os.getpid())
print '+++++++++++++++++++++++++++++++'
print hpy().heap()[0]
print '==============================='
pidstat('before doing anything')
docs = []
for doc in range(0, 10000):
docs.append([j for j in range(0, 1000)])
pidstat('after fetching all the docs into memory')
del docs
pidstat('after freeing the docs')
time.sleep(60)
L'output è il seguente:
=============================== before doing anything Linux 2.6.38-15-generic (hersheezy) 08/14/2012 _x86_64_ (4 CPU) 01:05:20 PM PID minflt/s majflt/s VSZ RSS %MEM Command 01:05:20 PM 5360 0.44 0.00 44768 9180 0.11 python +++++++++++++++++++++++++++++++ Partition of a set of 19760 objects. Total size = 1591024 bytes. Index Count % Size % Cumulative % Kind (class/dict of class) 0 19760 100 1591024 100 1591024 100 str =============================== =============================== after fetching all the docs into memory Linux 2.6.38-15-generic (hersheezy) 08/14/2012 _x86_64_ (4 CPU) 01:05:21 PM PID minflt/s majflt/s VSZ RSS %MEM Command 01:05:21 PM 5360 8.95 0.00 318656 279120 3.49 python +++++++++++++++++++++++++++++++ Partition of a set of 7431665 objects. Total size = 178359960 bytes. Index Count % Size % Cumulative % Kind (class/dict of class) 0 7431665 100 178359960 100 178359960 100 int =============================== =============================== after freeing the docs Linux 2.6.38-15-generic (hersheezy) 08/14/2012 _x86_64_ (4 CPU) 01:05:29 PM PID minflt/s majflt/s VSZ RSS %MEM Command 01:05:29 PM 5360 40.23 0.00 499984 460480 5.77 python +++++++++++++++++++++++++++++++ Partition of a set of 19599 objects. Total size = 1582016 bytes. Index Count % Size % Cumulative % Kind (class/dict of class) 0 19599 100 1582016 100 1582016 100 str ===============================
Come posso essere sicuro che questo la memoria viene restituita al sistema operativo?
possibile duplicato di [Perché la memoria non viene rilasciata nel sistema dopo query di grandi dimensioni (o serie di query) in django?] (Http://stackoverflow.com/questions/5494178/why-doesnt-memory-get- release-to-system-after-large-queries-or-series-of-quer) –