If efficient threading is desired I would have thought that these days GPUs are all the rage and that it would be worth looking into openCL and CUDA implementations for doing this.

On an unrelated note are there any thoughts on moving CCTBX to Python3? One issue, which may not be insurmountable is that SCons does not yet support Python3.

Rob



-----Original Message----- From: Graeme.Winter@diamond.ac.uk
Sent: Tuesday, August 1, 2017 10:16 PM
To: cctbxbb@phenix-online.org
Subject: Re: [cctbxbb] Should we enable boost threads in bootstrap?

Lee,

End game for us is moving to “proper” threading i.e. lots of threads / cores working on one problem in one address space - be it regular 20 core xeon or 64 core KNL

Boost threads came up in conversation today as a C++11 like threading model, so I wondered if it would be a stepping stone...

Don’t have this book, maybe should get it….

Cheers Graeme



On 1 Aug 2017, at 18:14, Lee O'Riordan <loriordan@lbl.gov<mailto:loriordan@lbl.gov>> wrote:

Graeme, Nigel,

I would be a little bit worried about Boost threads when it comes to our KNL port of cctbx. In this instance the use of OpenMP or Intel TBB (at least accordingly to Intel docs) would be optimal over boost threads (or pthreads, etc.)[see Intel Xeon Phi High Performance Programming, KNL edition P155 ---  no ebook, sorry]. That being said, there is no way to know unless we try it out first, but it isn't something we can test right now.

As for Threads vs MP, this again falls into our KNL port, where threads would be better suited (and become a necessity for optimal performance) when running on high-core count devices. If the OpenMP functionality exists, then maybe this would be a more portable way of taking advantage of all cores/hyperthreads.

In this instance I think turning boost threads on for a build-by-build basis would be better, rather than as a default? Though if I am wrong, feel free to correct me.

Best,
Lee.

On Tue, Aug 1, 2017 at 9:36 AM, Nigel Moriarty <nwmoriarty@lbl.gov<mailto:nwmoriarty@lbl.gov>> wrote:
Graeme

The short answer is "Why?" but that may start a very long discussion. There are a number of multiprocessing modules in easy_mp that seem to cover all the bases. Are there situations where threading is "better" to multiprocessing?

Articles on multiprocessing in cctbx.

https://www.phenix-online.org/newsletter/CCN_2017_01.pdf#page=6

https://www.phenix-online.org/newsletter/CCN_2013_07.pdf

https://www.phenix-online.org/newsletter/CCN_2013_01.pdf


Cheers

Nigel

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On Tue, Aug 1, 2017 at 7:54 AM, <Graeme.Winter@diamond.ac.uk<mailto:Graeme.Winter@diamond.ac.uk>> wrote:
Afternoon all,

Should we do this? Any opinions? Could be useful for threads in a semi-portable way...

Thanks & cheerio Graeme

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