[QE-users] use of blas&lapack from amd-optimized libflame 2.1 causes test failures in epw tests

[Tobias Kloeffel]

Another note, there seem to be problems using FFTW interface of MKL

export MKL_DEBUG_CPU_TYPE=5

with  AMD cpus. To get around this problem, one hast to additionally set

export MKL_CBWR=AUTO

Kind regards,
Tobias


On 2/3/20 8:46 AM, Tobias Kloeffel wrote:
> Recently I played around with some AMD EPYC cpus and the bad thing is 
> that I also saw some strange numbers when using libflame/aocl 2.1.
>
> The 'workaround' is probably to just use Intel's MKL. Since version 
> 2020 the MKL performs rather well when using AMD cpus, however, if you 
> want to get the best performance you have to additionally set:
>
> export MKL_DEBUG_CPU_TYPE=5
>
> which gives an additional 10-20% speedup with MKL 2020, while for 
> earlier versions the speedup is greater than 200%
>
> Kind regards,
> Tobias
>
> On 2/2/20 10:57 PM, Paolo Giannozzi wrote:
>> On Sun, Feb 2, 2020 at 10:23 PM Evgeny Permyakov <permeakra at gmail.com 
>> <mailto:permeakra at gmail.com>> wrote:
>>
>>     sidenote: I had to set  **orte_execute_quiet = true** in
>>     ~/.openmpi/mca-params.conf so mpi didn't mess with extra messages
>>
>>
>> thank you for  this useful piece of information: I got rid of those 
>> annoying messages
>>
>>     I don't use epw in my work and pwscf tests work just fine, but
>>     the fact that some tests failed bother me. Should I investigate
>>     it further and how? I'm not versed in QE code, I'm a humble user.
>>
>> investigating further would be a good thing, but it is not easy: one 
>> has to figure out which piece of code fails, then why. Even if one 
>> succeeds, very often the problem is in the library itself and  there 
>> is nothing that can be done.
>>
>> Frequent offenders are complex-valued routines (e.g. zdotc) that seem 
>> to follow two different incompatible conventions, but the symptom is 
>> a hard crash, not a wrong number.
>>
>> Paolo
>> -- 
>> Paolo Giannozzi, Dip. Scienze Matematiche Informatiche e Fisiche,
>> Univ. Udine, via delle Scienze 208, 33100 Udine, Italy
>> Phone +39-0432-558216, fax +39-0432-558222
>>
>>
>> _______________________________________________
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>
>
> -- 
> M.Sc. Tobias Klöffel
> =======================================================
> HPC (High Performance Computing) group
> Erlangen Regional Computing Center(RRZE)
> Friedrich-Alexander-Universität Erlangen-Nürnberg
> Martensstr. 1
> 91058 Erlangen
>
> Room: 1.133
> Phone: +49 (0) 9131 / 85 - 20101
>
> =======================================================
>
> E-mail:tobias.kloeffel at fau.de
>
> _______________________________________________
> Quantum ESPRESSO is supported by MaX (www.max-centre.eu/quantum-espresso)
> users mailing list users at lists.quantum-espresso.org
> https://lists.quantum-espresso.org/mailman/listinfo/users


-- 
M.Sc. Tobias Klöffel
=======================================================
HPC (High Performance Computing) group
Erlangen Regional Computing Center(RRZE)
Friedrich-Alexander-Universität Erlangen-Nürnberg
Martensstr. 1
91058 Erlangen

Room: 1.133
Phone: +49 (0) 9131 / 85 - 20101

=======================================================

E-mail: tobias.kloeffel at fau.de

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