> Date: Wed, 4 Jan 2012 19:10:28 +0100
> From: wmgcnfg@web.de
> To: mkgmap-dev@lists.mkgmap.org.uk
> Subject: Re: [mkgmap-dev] [PATCH v2] Performance improvement by removing unused elements before the style processing
>
> Hi Gerd,
>
> yes of course I am interested, Send me all information you have.
>
> Thanks
> WanMil
>
> > Hi WanMil,
> >
> > I tested the patch with my tiles for Saarland. I can confirm a reduction of
> > processing time ~ 6% compared to r2160, and also a reduction for the peek
> > value of heap memory usage (238M -> 210M), so that's both good!
> > BUT I also see a difference in one of the seven output img files (plus the
> > resulting gmapsupp.img), and I think this is not intended. Both files have
> > the same size, but are different in many bytes.
> > Let me know when I should send details, maybe the new result is better than
> > the old ;-)
> >
> > Ciao,
> > Gerd
> >
> >
> > WanMil wrote
> >>
> >> The 2nd patch fixes the remaining problems:
> >> 1. Ways without tags but referenced by relations are no longer removed
> >> (they might be tagged by the relation style file and could therefore
> >> appear in the map)
> >> 2. Intersection of ways with the tile bounding box is now checked
> >> instead of only checking that at least one point is contained in the
> >> bounding box. Only very few ways are affected by this but otherwise
> >> routing problems are possible.
> >>
> >> The performance improvement seems to be good (measured with my test map):
> >> r2159: ~250s
> >> patched: ~225s
> >>
> >> I also expect (although I haven't tested) that the max memory
> >> requirement of mkgmap is decreased. I think max mem is used when the
> >> style file is just processed. At this stage all raw OSM elements and all
> >> style file processed elements are kept in memory. With the patch the
> >> number of OSM elements is noticeably reduced.
> >>
> >> WanMil
> >>
> >>> Hi,
> >>>
> >>> this is another performance improvement:
> >>>
> >>> Usually the mkgmap input tiles are larger than the processed bounding
> >>> box (splitter parameter overlap). So there are much many elements which
> >>> are processed but thrown away at a late step in mkgmap.
> >>>
> >>> The patch tries to remove them much earlier before the style files are
> >>> processed and before the LocationHook starts (which ignores them but
> >>> that must also be calculated).
> >>>
> >>> The patch contains one drawback:
> >>> Ways which have all its points outside the bounding box of the tile but
> >>> which cross the tile are also removed. If that's a point the patch must
> >>> be improved.
> >>>
> >>> Have fun!
> >>> WanMil
> >>>
> >>>
> >>> _______________________________________________
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> >>> mkgmap-dev@.org
> >>> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
> >>
> >>
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> >>
> >
> >
> > --
> > View this message in context: http://gis.638310.n2.nabble.com/PATCH-v1-Performance-improvement-by-removing-unused-elements-before-the-style-processing-tp7144978p7149735.html
> > Sent from the Mkgmap Development mailing list archive at Nabble.com.
> > _______________________________________________
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> > mkgmap-dev@lists.mkgmap.org.uk
> > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev
>
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