[ Warning: I'm new to Python. Don't know it at all really yet, but had
to examine some 3rd party code because of performance problems with it.
]
Here's a code snippet:
i = 0
while (i < 20):
i = i + 1
(shellIn, shellOut) = os.popen4("/bin/sh -c ':'") # for testing, the
spawned shell does nothing
print 'next'
# for line in shellOut:
# print line
On my system (AIX 5.1 if it matters, with Python 2.4.3), this simple
loop spawning 20 subshells takes .75 sec. Ok, that's reasonable. Now,
if I uncomment the two commented lines, which loop over the empty
shellOut array, the progam now takes 11 secs. That slowdown seems
very hard to believe. Why should it slow down so much?
John.
---
Tried it on my comp (battered up winXP laptop on it's last breath) with the
following change...
(shellIn, shellOut) = os.popen4("cmd ")
and the performance with or without the inserted for loop is roughly equivalent
albeit a /bit/ slower with the for loop is but I would need timers really
make it stand out (under 1 second difference).
All in all, rough estimation is that both take more or less 4 seconds to
complete which is what I would expect knowing my system...
Anyways, is what I got...
Hope it helps somehow
Éric :D.
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