libxsmm MNK, SSE and other inconsistencies

Johannes Wagner johanne... at gmail.com
Mon Jan 18 16:32:47 CET 2016


Hi Alfio,
thanks for your reply. I also opted for the AVX setting. I just thought 
that the this libxsmm cp2k flag is somehow aligned with the cp2k needs. 
I'll also post this at their git page.

On Saturday, January 16, 2016 at 2:41:21 PM UTC+1, Alfio Lazzaro wrote:
>
> Hi Johannes,
> the MNK values are not the same, libxsmm produces less kernels (probably 
> related to specific benchmarks used by libxsmm developers). I cannot speak 
> about LIBXSMM (you should ask in their git forum), however I would suggest 
> to use what is in the toolchain for MNK, which is the most general case for 
> CP2K kernels. Concerning the other parameters, depending on your system, I 
> would suggest to change SSE in AVX=1 (sandybridge/ivydridge) or 2 
> (haswell/broadwell) (AVX=3 is Intel KNL, so it doesn't not exist yet).
>
> Alfio
>
>
>
>
> Il giorno venerdì 15 gennaio 2016 16:33:11 UTC+1, Johannes Wagner ha 
> scritto:
>>
>> hey all,
>> I have a question regarding installing libxsmm. If downloaded from git (
>> https://github.com/hfp/libxsmm/archive/1.1.1.tar.gz), the make.sh file 
>> includes an -cp2k flag that sets MNK options to:
>>
>>  MNK=" \
>>
>>     23, \
>>
>>     6, \
>>
>>     14 16 29, \
>>
>>     14 32 29, \
>>
>>     5 32 13 24 26, \
>>
>>     9 32 22, \
>>
>>     64, \
>>
>>     78, \
>>
>>     16 29 55, \
>>
>>     32 29 55, \
>>
>>     12, \
>>
>>     4 5 7 9 13 25 26 28 32 45"
>>
>>
>> along with 
>>
>> ALIGNED_LOADS=1 ALIGNED_STORES=1 PRECISION=2 SYM=1 SSE=3
>>
>>
>> but the cp2k source's toolchain installer sets it to 
>>
>>
>> MNK="1 4 5 6 8 9 13 16 17 22 23 24 26 32"
>>
>>
>> along with
>>
>> SSE=1 JIT=1 PREFETCH=1
>>
>>
>> Now why is this inconsistent? Which is the "correct" MNK options, or does 
>> the former comprise all cases from the latter? And the option SSE=3 doesn't 
>> even exist according to the Makefile.inc. Only SSE=1 or AVX=1|2|3 (which at 
>> least is sort of what the libxsmm.pdf in the libxsmm documentation folder 
>> says).
>>
>
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