[mkgmap-dev] [PATCH v2] Performance improvement by removing unused elements before the style processingFrom GerdP gpetermann_muenchen at hotmail.com on Wed Jan 4 09:29:43 GMT 2012
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 >> >> >> _______________________________________________ >> mkgmap-dev mailing list >> mkgmap-dev at .org >> http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > > > _______________________________________________ > mkgmap-dev mailing list > mkgmap-dev at .org > http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev > -- 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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