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List:       kde-kimageshop
Subject:    Re: threading libs
From:       Bavo De Ridder <bavodr () poboxes ! com>
Date:       1999-08-28 9:20:35
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On Sat, 28 Aug 1999, Sven Fischer wrote:
>Carsten Pfeiffer <carpdjih@cetus.zrz.TU-Berlin.DE> writes:
>
>> I don't know where to put the threading lib... should that be in kdelibs
>> or just in KIS? I'd prefer kdelibs, so other programs could benefit from
>> it.
>> The configure shouldn't be too hard, then.
>
>I just want to note that Qt still isn't thread safe, so GUI tasks can
>only be done in one single thread. See www.troll.no for this.
>

This is indeed true !!!

I want to use this mail to emphazise again some things:

- multithreading only gives (slight) performance increases on SMP systems
- multithreading IO also gives (slight) performance increases on single
  processor systems, although kimageshop doesn't have IO problems I guess
- real performance gains can and should be achieved using the following things
    a) use MMX/..... when available, this will give a real performance boost
    b) use BLAS 1/2/3 libraries when available
    c) DON'T 'and I repeat DON'T) write your own numerical libraries
       if you want good numerical libaries, search the web for 'BLAS', ...

MPICH is also a good candidate. Good implementations of MPI should scale on SMP
systems and clusters (if communication links > 100Mb are used). I am no expert
on MPI, .... so I guess we will need to contact someone else.

I work at the computer science departement of the university of louvain
(Belgium). I will ask our local MPI guru's for some information.


BDR

>Greets, Sven
>
>-- 
>  __ 
> /_. Sven Fischer - Kastanienweg 33, D-52074 Aachen, +49-(0)241-875173
>/ /                 http://www.kawo2.rwth-aachen.de/~sven - GPG key available

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