<div dir="ltr">On Sun, Sep 18, 2016 at 4:24 PM, Roland Haas <span dir="ltr"><<a href="mailto:rhaas@illinois.edu" target="_blank">rhaas@illinois.edu</a>></span> wrote:<br><div class="gmail_extra"><div class="gmail_quote"><blockquote class="gmail_quote" style="margin:0px 0px 0px 0.8ex;border-left-width:1px;border-left-color:rgb(204,204,204);border-left-style:solid;padding-left:1ex">Hello Erik,<br>
<span class="gmail-"><br>
> It's strange that code without "-xHost" does not run on the head node. What<br>
> other compiler options are there? The only reason I can see is that the<br>
> Intel compiler has been installed in a special way to use additional<br>
> compiler flags, and these flags make the code not work any more on Sandy<br>
> Bridge.<br>
</span>It is some runtime detection that fails. I get:<br>
--8<--<br>
Please verify that both the operating system and the processor support Intel(R) F16C instructions.<br>
--8<--<br>
and adding -xHost complains that "icc: command line warning #10121:<br>
overriding '-xCORE-AVX-I' with '-xHost'" so it seesm as if some vectorization is enabled by the cray cc wrapper.<br>
<span class="gmail-"><br>
> To my knowledge, the processors accept the same machine instructions. The<br>
> CPU tuning might be different.<br>
</span>Is this also true for vectorization? Or maybe this really is just a<br>
lack of OS support for the AVX registers on the login nodes. -xAVX<br>
seems to work fine and the only difference (according to the man page<br>
for icpc) are "Float-16 conversion instructions and the RDRND<br>
instruction". Float16 conversion would fit the F16C acronym in the error message.<br></blockquote><div><br></div><div>The best option for us is then probably "-xHost -axCORE-AVX-I". This ensures (-x) that the code runs on the front end, but it will apply code optimizations (-ax) for the compute nodes.</div><div><br></div><div>-erik</div></div><div><br></div>-- <br><div class="gmail_signature">Erik Schnetter <<a href="mailto:schnetter@cct.lsu.edu" target="_blank">schnetter@cct.lsu.edu</a>><br><a href="http://www.perimeterinstitute.ca/personal/eschnetter/" target="_blank">http://www.perimeterinstitute.ca/personal/eschnetter/</a></div>
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