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Subject: Re: [OMPI users] MPI_Comm_accept - Busy wait
From: Thatyene Louise Alves de Souza Ramos (thatyene_at_[hidden])
Date: 2011-10-14 14:47:48


Thank you for the explanation! I use "-mca mpi_yield_when_idle 1" already!

Thank you again!

---
Thatyene Ramos
On Fri, Oct 14, 2011 at 3:43 PM, Ralph Castain <rhc_at_[hidden]> wrote:
> Sorry - been occupied. This is normal behavior. As has been discussed on
> this list before, OMPI made a design decision to minimize latency. This
> means we aggressively poll for connections. Only thing you can do is tell it
> to yield the processor when idle so, if something else is trying to run, we
> will let it get in there a little earlier. Use -mca mpi_yield_when_idle 1
>
> However, we have seen that if no other user processes are trying to run,
> then the scheduler hands the processor right back to you - and you'll still
> see that 100% number. It doesn't mean we are being hogs - it just means that
> nothing else wants to run, so we happily accept the time.
>
>
> On Oct 14, 2011, at 12:21 PM, Thatyene Louise Alves de Souza Ramos wrote:
>
> Does anyone have any idea?
>
> ---
> Thatyene Ramos
>
> On Fri, Oct 7, 2011 at 12:01 PM, Thatyene Louise Alves de Souza Ramos <
> thatyene_at_[hidden]> wrote:
>
>> Hi there!
>>
>> In my code I use MPI_Comm_accept in a server-client communication. I
>> noticed that the server remains on busy wait whereas waiting for clients
>> connections, using 100% of CPU if there are no other processes running.
>>
>> I wonder if there is any way to prevent this from happening.
>>
>> Thanks in advance.
>>
>> Thatyene Ramos
>>
>
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