[mkgmap-dev] [PATCH v1] Experimental support for multi-threading

Mon May 11 09:59:08 BST 2009

Johann Gail wrote:
>
>> As a lot of the processing has to be done in sequence, the
>> opportunities for using multiple threads are somewhat limited.
>> However, the attached patch parallelises:
>>
>> 1 - processing of ways from OSM form to MapLine/MapRoad.
>>
>> 2 - processing of cities
>>
>> 3 - processing of POIs
>>
>> 4 - processing of polylines and polyshapes within each division
>>  
> In this situation (a lot of sequential processing), wouldn't it be an 
> better approach to start several processes of mkgmap with different 
> tiles?
>
> This could be fully parallelized without dependencies.
>
> Afterwards the different tiles had to be merged into an single img 
> file. This process could be started in another extra process with the 
> finishing of the first tile.
>
>
I would support that approach too. If you parse several .osm or .gz 
files in one command to mkgmap. It should try to run them in several 
processes respecting the maximum java heapspace you give (so split up 
the heapspace to the processes). running two instances of mkgmap I get 
often problems with Java heap space (even though there is enough 
available). I suspect there is some other error.
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