[Beowulf] Here we go again

[Peter Kjellström]

On Fri, 13 Dec 2019 09:54:02 +0800
Miguel Dias Costa <migueldiascosta at gmail.com> wrote:
...
> I have been using MKL_DEBUG_CPU_TYPE=5 on Naples with the 2018
> versions of MKL with good results, but when switching to 2019
> versions some application tests started failing (dramatically wrong
> results) in FFT dependent stuff (and no failure without
> MKL_DEBUG_CPU_TYPE=5).
> 
> I could also reproduce this behaviour in some of MKL's own FFT
> examples, so it shouldn't be hard for other people to check.
> 
> Setting both MKL_DEBUG_CPU_TYPE=5 and MKL_CBWR=COMPATIBLE solved the 
> issue, and MKL is still using AVX2, but it does mean one needs to be 
> careful with MKL_DEBUG_CPU_TYPE...

We've had similar (but maybe not as serious) issues even on Intel
Skylake using MKL and AVX2 or AVX512. That is, using MKL_CBWR needed
for sanity.

Could you dig up which of the simple Intel tests that fail? I'd love to
try that on my Rome box (and skylake setup for reference).

/Peter