[mkgmap-dev] [PATCH]mkgmap performance part 2

Sun Dec 25 16:33:46 GMT 2011

Hello Gerd,

you do a lot of thinks, especially improving the performance of splitter and mkgmap. That's great, thank you. Can you please upload your patched jar-file? For me and some other people in the list patching is pretty tricky... ;)

Cheers,
Martin

Am 24.12.2011 um 15:13 schrieb GerdP:

> Hello list,
> 
> I got no feedback regarding my last performance patch for mkgmap, so I don't
> know if nobody tested it. Anyway, here are a few more small suggestions for
> changes (can be applied
> http://gis.638310.n2.nabble.com/file/n7123938/mkgmap_performance_2.patch
> mkgmap_performance_2.patch  on r2145 and gmap-mdr branch 2144 as well) :
> On my dual-core machine, creating a gmapsupp.img of ~ 91MB (Niedersachsen)
> with max-jobs=2 required ~ 352 secs with r2145, and 268 secs (~ 25% less)
> with my previous patch + this one, so I think it is worth trying.
> 
> For removeShortArcsByMergingNodes:
> - The IdentityHashMap arcCounts counts arcs, but the only result that is
> used is wether or not an arc was found. My patch replaces this frequently
> used map and uses a bit in Coord instead. 
> 
> - the current algorithmn tries to find replacements for each point, this is
> quite costly. One more bit in Coord reduces the number of loops from >
> 1.000.000 to ~1000.
> 
> For LocationHook:
> I've replaced the getUsedLocationTags() by testHasAllTags(). This just
> returns true if all tags in List remainingLevels are existing, instead of
> merging HashSets to get the same result.
> 
> For RuleSet / RuleIndex:
> I've replaced the HashSet<Integer> by BitSet. This is faster because we
> don't have to use 
> Collections.sort(candidates);
> to handle duplicate rules.
> 
> Gerd
> 
> 
> 
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