[Users] ET on KNL.

[Eloisa Bentivegna]

On 24/03/17 14:17, Erik Schnetter wrote:
> On Fri, Mar 24, 2017 at 8:43 AM, Eloisa Bentivegna
> <eloisa.bentivegna at ct.infn.it <mailto: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".

Hi all,

I have now tried all of these options and continue getting the message

===============================================================
INFO (Vectors): Using vector size 4 for architecture AVX (64-bit
precision)
===============================================================

Can linking to system libraries compiled for the BDW architecture lead
to this message, even if the Cactus executable itself was build on a KNL
with the KNL flags?

In any case, I have created a pull request of Simfactory with the KNL
configuration I am using now. At least it's a starting point.

Best,
Eloisa