[Qgis-psc] Proposal to support multi-threaded development

[Tim Sutton]

Hi Marco


On Tue, Nov 26, 2013 at 10:01 AM, Marco Hugentobler <
marco.hugentobler at sourcepole.ch> wrote:

> Hi all
>
> I'm (obviously) a big supporter of threaded rendering, therefore close to
> say +1. However Paolos concerns are valid. There has been a GSOC project
> and a second project already and there is still no multithreaded rendering
> in QGIS master. Maybe we could request a detailed work plan this time with
> the overall project broken down to smaller goals. Each goal must have a
> clear deadline and merging needs to leave the codebase in a well-defined
> and useable state (so that there is a benefit even if the project does not
> end up 100% complete).
>
> To illustrate what I mean, I can say a few words about the multi-threaded
> rendering in QGIS enterprise. The goal here was to have a responsible UI
> and fast data browsing without redesign of the codebase. The probably
> critical difference to the multi-threaded render project in master is that
> it does not attempt to provide real concurrent iterating of the
> provider/layers (but 1.9x and afaik even master do not provide that
> anyway). If the main map / composer / globe needs to render, it needs to
> query a function to see if another component is already iterating over the
> layers.
>
> If the concurrent iterating is the most difficult thing to achieve
> (Martin, please correct me if not), wouldn't it be good to start with
> implementing the QtConcurrent things in QgsMapRenderer, the image
> compositing and the protection of some critical points from access by
> multiple threads? This would already bring great benefit for the user
> experience. Finally do the concurrent iterating as a second part of the
> project.
>
>
Just curious - do you guys plan on merging your multi-threaded
implementation too - or is it going to remain in 1.8? I ask because it
would be a pity for others to duplicate the work. Nice video you put on
youtube showing off your multithreading Marco!

@andreas Unfortunately the person who I thought might like to co-sponsor
the threading support had other plans.



Regards

Tim


>
>
> Regards,
> Marco
>
>
>
>
>
>
>
>
>
> On 24.11.2013 17:30, Andreas Neumann wrote:
>
>> Hi PSC,
>>
>> In October Peter and Saber proposed a project to work on the
>> multi-threaded rendering. The new Vector API (which was also co-funded
>> by the QGIS user group in Switzerland) was the preparation for this
>> follow-up work. The development work on the multi-threaded rendering
>> would be carried out by Martin Dobias.
>>
>> Lutra Consulting, the current employer of Martin, is looking to raise
>> Euro 20k for this project. The QGIS user group pays CHF 3000.- this year
>> and will most likely pay a similar amount again next year.
>>
>> I am asking the PSC that the international QGIS project is also
>> co-funding this project, perhaps with approx. Euro 5k.
>>
>> Marco Hugentobler worked on multi-threaded rendering in QGIS enterprise
>> (based on the 1.9x branch). Horst demoed this version at the recent QGIS
>> CH coordination meeting. It looks very promising as it does not block
>> the UI. Users can navigate to a different extent while QGIS is still
>> rendering. QGIS would then cancel the old render threads and start with
>> the new threads. But this work is not compatible with the 2.x
>> development branch. However, it shows the potential of threaded rendering.
>>
>> What is the opinion of the PSC? Can the international group co-fund this
>> initiative?
>>
>> Andreas
>>
>> PS: see also discussion started here -
>> http://lists.osgeo.org/pipermail/qgis-developer/2013-October/029066.html
>> _______________________________________________
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>> Qgis-psc at lists.osgeo.org
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>>
>
>
> --
> Dr. Marco Hugentobler
> Sourcepole -  Linux & Open Source Solutions
> Weberstrasse 5, CH-8004 Zürich, Switzerland
> marco.hugentobler at sourcepole.ch http://www.sourcepole.ch
> Technical Advisor QGIS Project Steering Committee
>
>
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>



-- 
Tim Sutton - QGIS Project Steering Committee Member
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