I have some simple threaded code... If I run this with an arg of 1 (start one thread), it pegs one cpu, as I would expect. If I run it with an arg of 2 (start 2 threads), it uses both CPUs, but utilization of both is less than 50%. Can anyone explain why?
I do not pretend it's impeccable code, and I'm not looking for a
critiqe of the code per se, excepting the case where what I've written
is actually *wrong*. I hacked this together in a couple of minutes,
with the intent of pegging my CPUs. Performance with two threads is
actually *worse* than with one, which is highly unintuitive. I can
accomplish my goal very easily with bash, but I still want to
understand what's going on here...
The OS is Linux 2.6.24, on a Ubuntu base. Here's the code:
Thanks
-=-=-=-=-
#!/usr/bin/python
import thread, sys, time
def busy(thread):
x=0
while True:
x+=1
if __name__ == '__main__':
try:
cpus = int(sys.argv[1])
except ValueError:
cpus = 1
print "cpus = %d, argv[1] = %s\n" % (cpus, sys.argv[1])
i=0
thread_list = []
while i < cpus:
x = thread.start_new_thread(busy, (i,))
thread_list.append(x)
i+=1
while True:
pass
--
Derek D. Martin
http://www.pizzashack.org/
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