[Tutor] Python performance resources & resouce usage hints

[Hugo González Monteverde]

Liam Clarke wrote:

> Each thread's run() method basically looks like this -
> 
>         while True:
>             try:
>                 data = self.queue.get(False)
>                 self.DAO.send_data(data)
>             except Empty:
>                 if self.shutdown:
>                     print "\DAO closing"
>                     return
>                 continue
> 
> 

Hi Liam,

I checked the response by Kent. I completely agree with him in that the 
problem is the endless polling you have.

However, you do not have to implement a sleep in your loop; the main 
issue may be that you are not using the facilities of the 'get' method 
in the queue. From the queue docs:

get(  	[block[, timeout]])
     Remove and return an item from the queue. If optional args block is 
true and timeout is None (the default), block if necessary until an item 
is available. If timeout is a positive number, it blocks at most timeout 
seconds and raises the Empty exception if no item was available within 
that time. Otherwise (block is false), return an item if one is 
immediately available, else raise the Empty exception (timeout is 
ignored in that case).


You are not using the optional timeout and blocking which 'get' provides (!)

Try setting it and see your CPU usage go down. This will implement 
blocking, and the queue will be used as soon as data is there.	Set block 
to True and a timeout if you need to use it (looks like you only need 
blocking)

         while True:
              try:
                 data = self.queue.get(True)
                 self.DAO.send_data(data)

Hope that helps,

Hugo