[cctbxbb] Removal of Boost.Thread support
Jeffrey Van Voorst
vanv0059 at umn.edu
Thu Aug 16 11:09:48 PDT 2012
On 8/16/12 11:17 AM, Nathaniel Echols wrote:
> On Thu, Aug 16, 2012 at 4:58 AM, Luc Bourhis <luc_j_bourhis at mac.com> wrote:
>>> A secondary problem is that OpenMP is incompatible with the multiprocessing
>>> module
>> Could you enlighten me as to the exact nature of the problem?
> Well, you were the one who figured out the explanation, so I'm just
> paraphrasing (poorly) what you told me, but: conventional
> multithreading does not play nice with OpenMP threads. Since Python
> multiprocessing (and/or threading, which is used by multiprocessing)
> involves multiple threads (an implementation detail that will not be
> obvious to the casual Python programmer, thanks to the GIL), it
> crashes OpenMP. I can dig up the original emails which explained this
> if you want.
>
> -Nat
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I thought multiprocessing was to get around the issues of the GIL and
use processes instead of threads, but provide the same (or as similar as
possible) api as the threading module. At least, that is what is stated
on the multiprocessing module page; I haven't tried multiprocessing +
OpenMP so I cannot verify that the statements on the multiprocessing
page are indeed correct.
--Jeff
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