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Subject: Re: [OMPI users] knem support in ompi
From: George Bosilca (bosilca_at_[hidden])
Date: 2013-09-04 07:15:09


Small messages, i.e. their length is under btl_sm_eager_limit, always use normal SM. KNEM usage is restricted only for messages over either the eager size or the btl_sm_knem_dma_min (if KNEM supports DMA).

  George.

On Sep 4, 2013, at 12:47 , Alina Sklarevich <alinas_at_[hidden]> wrote:

> Hi,
>
> I am building ompi v1.6 with knem support and I see that when knem is enabed from the command line
> it is used for all message sizes in SM btl. There is no threshold for when to start using knem - starting
> which message size.
> This makes the performance of small messages worse since it also uses knem.
> Maybe a certain "knem threshold" should be added to specify when to use SM btl's send and when to start using knem.
>
> What do you think?
>
> Alina.
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