[mapserver-users] Enhancing MapServer performance with GPUs

[Adam Eskreis]

It's been a while since I've looked at the Mapserver code, but if I'm not
mistaken it uses the fixed function pipeline for OpenGL which isn't going
to be able to take advantage of all of those wonderful shader cores very
well.  If you wrote your own renderer using OpenGL 4.0+, you might be able
to get a substantial boost in rendering performance, but as Paul said,
rendering may not be your bottleneck.  You should ensure that it is before
spending a lot of money on GPU servers.  Also something to keep in mind,
when you render with OpenGL you must convert all of your polygons into
triangle meshes, which can be an extremely costly operation, especially for
concave polygons that contain holes, which are quite common in GIS data.


On Mon, Jun 16, 2014 at 5:42 PM, Paul Ramsey <pramsey at cleverelephant.ca>
wrote:

> Non-trivial places time can be spent:
>
> - CGI startup (if you aren't using FastCGI)
> - reading layers (if you have a lot of them! it's only a ms or two per
> layer, but if you have 100 layers...)
> - reading data
> - rendering data
> - compressing output images (more than you'd expect)
>
> I'd expect GPU assisted rendering to be a win only for a narrow
> minority of cases, it's not a predominant time sink as often as one
> would expect. Plus for all the speed once you have the GPU chain set
> up, the setting up of the GPU can be costly, and for a CGI program
> like MapServer, that's a big deal.
>
> P
>
>
> On Sun, Jun 15, 2014 at 2:57 PM, Even Rouault
> <even.rouault at mines-paris.org> wrote:
> > Le dimanche 15 juin 2014 23:50:05, Visit Hirankitti a écrit :
> >> Dear list memers,
> >>
> >> My name is Visit, a newbie of this forum. I have been using MapServer
> for
> >> at least 4 years now on many research projects. It has served my
> research
> >> projects quite well.
> >>
> >> Recently I am using MapServer to develop a real-world enterprise web
> >> application.
> >> I am developing a web-based GIS application using MapServer to serve
> >> thousands of users, and one of overheads of the system is on the map
> >> rendering provided by MapServer.
> >>
> >> At the moment the server I use to run MapServer doesn't have a graphic
> card
> >> (i.e. GPUs), but I wonder if I really want high performance of
> >> map-rendering from MapServer, can a graphic card (i.e. GPUs) equipped
> with
> >> the server enhance MapServer's map rendering speed and hence improve its
> >> map service speed?
> >>
> >> As a graphic card contains hundreds of GPU cores, e.g. NVDIA CUDA
> platform,
> >> and each core can compute and draw polygons in parallel, so I think this
> >> can improve the speed of map rendering (if used with MapServer)
> >> substantially. Do I understand this correctly?
> >
> > You'll have to profile where the time is exactly spent in MapServer. If
> it is
> > in pulling data from sources, or in the rendering part itself. There's a
> > OpenGL backend available in recent MapServer versions that could
> potentially
> > speed up rendering, but it is likely a bit experimental and might need
> more
> > work.
> >
> >>
> >> Thanks for your advice in advance,
> >>
> >> Visit Hirankitti Ph.D.
> >>
> >> Intelligent Communication and Transportation Lab
> >> King Mongkut's Institute of Technology Ladkrabang
> >> Thailand
> >
> > --
> > Geospatial professional services
> > http://even.rouault.free.fr/services.html
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