[Users] ET on KNL.

[Erik Schnetter]

On Fri, Mar 24, 2017 at 8:43 AM, Eloisa Bentivegna <
eloisa.bentivegna at ct.infn.it> wrote:

> Hi all,
>
> still on the KNL topic, I realize there was a question I ignored, and
> which perhaps is worth pursuing.
>
> On 01/03/17 21:43, Ian Hinder wrote:
> > Eloisa: does Carpet report the vector size of the KNL as 8?  From the
> > wikipedia entry, I would expect that to be the case, but I think you
> > mentioned to me that it was reporting 4.
>
> That's correct. In my output I find:
>
> ===============================================================
> INFO (Vectors): Using vector size 4 for architecture AVX (64-bit precision)
> ===============================================================
>
> Is this not supposed to be so? And in this case, is there anything I can
> do about it?
>

You should see a vector size of 8, and a message containing "AVX512 (64-bit
precision)". If you do not do this, then there is a problem with the
compiler options -- this decision is made at compile time. You might need
to specify "-march=knl" to GCC, or a similar option to the Intel compiler,
or you could build on a KNL node and use "-march=native" or "-xHost".

-erik

> Eloisa, are you using LoopControl?
>
> Yes.
>
> Eloisa
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-- 
Erik Schnetter <schnetter at cct.lsu.edu>
http://www.perimeterinstitute.ca/personal/eschnetter/
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