Hi Folks, I have recently gained access to a monster box containing 16 3GHz cores and 32 G of memory so I thought it would make an ideal machine to test a multi-threaded version of mkgmap. 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 At this time, the performance gain is useful but not stunning (typically, 25-30% speedup when using at least 4 cores). There is a small gain even when only using 2 cores. With the patch in place, it will default to using as many threads as you have cores. If you wish, you can explicitly specify the number of threads to use with the --num-threads=N option. You may specify more threads than you have cores but it won't make it any faster. Specifying less threads than cores is useful for testing purposes or disabling the parallel processing (by specifying just 1 thread). One side effect of the multi-threading is that the elements are written to the output file in a random order. If you specify the (existing) --preserve-element-order option, the order will be preserved but all of the threading will be disabled! The patch has received some testing using mapsource and I think I have removed the worst of the bugs but I would very much appreciate it if people could try it out and see if it causes any breakage. Obviously, I would also like to know how well it performs. As it has only been tested under Linux any reports from other platforms would be especially useful. Cheers, Mark