Paralellisation information

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Paralellisation information

Postby dagosta » Thu Mar 22, 2018 9:40 am

Dear All,

I am running a GW calculation for the bands of a bulk material. I wish to know how to optimize the memory usage on my cluster, but I was not able to find information on Yambo website.

For example, what the PAR_def_mode does? In the input file, it says "balanced, memory, workload", so I assume "memory" distributes the memory usage evenly to all processes, while workload does the same for the load. Am I right?

Best regards,
Roberto
Roberto D'Agosta
Nano-Bio Spectroscopy Group
Av de Tolosa 72
Donostia-San Sebastian
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Re: Paralellisation information

Postby Daniele Varsano » Thu Mar 22, 2018 9:55 am

Ciao Roberto,
you can find some documentation on parallelization strategies:
http://www.yambo-code.org/wiki/index.ph ... strategies
As a general rule, in order to distribute memory among cpus, the best option is to parallelize along bands (c,v).

If something it is not clear, or you need further clarifications do not hesitate to post in the forum.

Bests,

Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/
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Re: Paralellisation information

Postby Davide Sangalli » Fri Mar 23, 2018 9:49 am

Dear Roberto,
in case you do not want to care about yambo parallelization input variables.

Your interpretation is correct. The "memory" strategy should maximize the memory distribution.
However it is a recent variable and not very much tested, since all yambo developers are setting up by hand the parallel variables in the input file.

Let us know if it works properly.

Best,
D.
Davide Sangalli, PhD
CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) and MaX Centre
http://www.ism.cnr.it/en/davide-sangalli-cv/
http://www.max-centre.eu/
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Re: Paralellisation information

Postby dagosta » Fri Mar 23, 2018 9:50 am

Ciao Daniele,

Thanks for the prompt reply. Another question that might seems stupid - but I was not able to find an answer. My log and report files do not include any information about the allocated or used memory. Is there a flag to have a more verbose output I should use in Yambo input file?

Thanks and all the best,
Roberto
Roberto D'Agosta
Nano-Bio Spectroscopy Group
Av de Tolosa 72
Donostia-San Sebastian
Spain
dagosta
 
Posts: 9
Joined: Thu Mar 22, 2018 8:45 am

Re: Paralellisation information

Postby Daniele Varsano » Fri Mar 23, 2018 9:56 am

Ciao Roberto,
in order to have memory information you should set a flag in compilation:
Code: Select all
./configure --enable-memory-profile etc.


Best,
Daniele
Dr. Daniele Varsano
S3-CNR Institute of Nanoscience and MaX Center, Italy
MaX - Materials design at the Exascale
http://www.nano.cnr.it
http://www.max-centre.eu/
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Re: Paralellisation information

Postby Davide Sangalli » Fri Mar 23, 2018 9:56 am

In the log file you should find messages when a variable which requires a significant amount of memory is allocated and de-allocated.

If you need more info you can compile yambo with the configure option
--enable-memory-profile (it just works in the last release I think)
You may even find useful to compile it with
--enable-time-profile

Best,
D.
Davide Sangalli, PhD
CNR-ISM, Division of Ultrafast Processes in Materials (FLASHit) and MaX Centre
http://www.ism.cnr.it/en/davide-sangalli-cv/
http://www.max-centre.eu/
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Re: Paralellisation information

Postby dagosta » Fri Mar 23, 2018 11:57 am

Dear Davide and Daniele,

Thanks for your reply. I will try to see if I can see differences on how memory or workload are distributed. I will also compile YAMBO with that flag.

Best regards,
Roberto
Roberto D'Agosta
Nano-Bio Spectroscopy Group
Av de Tolosa 72
Donostia-San Sebastian
Spain
dagosta
 
Posts: 9
Joined: Thu Mar 22, 2018 8:45 am


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