[IPython-User] Re-entrant?

reckoner reckoner@gmail....
Tue Aug 24 08:06:17 CDT 2010


Brian:

If you submit multiple work items to an engine via the queue you mention 
and then do *not* block, how do you know when a particular work item has 
finished? I know a PendingResult can be retained, but using it to get 
the res._result blocks until that work item is completed. This basically 
bypasses the benefit of submitting a nonblocking work item, since if you 
try to get at the result later, you will have to block to get it.

Am I misunderstanding something here? I'm talking mainly about
MultiEngineClients, not task clients.

Thanks for all the great work.



On 8/23/2010 8:56 PM, Brian Granger wrote:
> On Sat, Aug 21, 2010 at 7:13 AM, Darren Govoni<darren@ontrenet.com>  wrote:
>> Hi,
>>   I have two questions.
>>
>> 1) If I have a MultiEngineClient that I execute a function across the
>> nodes and don't block (or do). Then I do it again before the first
>> finished, will this cause any problems from a iPython point of view?
>
> I am not quite sure what you are asking here.  But if the engines are
> busy when you send additional work for them to do, it is not a
> problem.  The controller maintains a work queue for each engine and
> that work queue can receive additional work items while the engines
> work.  Does that answer this part of your ?.
>
>> 2) Can I create 2 MultiEngineClients over the same cluster of servers
>> and make simultaneous calls? How is this handled on the server nodes?
>
> It is first come, first server.  The queue for each engine that the
> controller maintains is a standard FIFO queue.  If multiple clients
> are submitting work to an engines queue, the commands are just
> interleaved in the order they are received.  BUT, there is only a
> single namespace on each engine, so if different clients overwrite
> each others variables, that will really happen.
>
> Cheers,
>
> Brian
>
>> Thanks
>> Darren
>>
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>
>
>


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