Hi Gerd, I think it's even more in combination with DEM. I usually use 6 of my 8 cores and ending up with 10 to 12 GB of heap. So I definitely agree with you available heap somehow needs to be considered as well. Not only CPU cores. Btw. for CFD/FEM analysis the simulation is usually is faster if you only use physical cores, not the 'virtual' ones. Don't know how mkgmap will behave. Henning On 05.02.2018 15:28, Gerd Petermann wrote:
Hi Mike,
thought about this again. Maybe this change is too simple. With multiple jobs one also needs more heap (-Xmx JRE option). If you create rather large tiles with splitter (max-nodes=1600000) you need 0.5 - 1 GB for each job. Not sure what happens when a user creates a map with 10 tiles on an 8-core machine without any -Xmx option.
I fear this will result in OutOfMemory exception, so better check the available heap as well.
Gerd
________________________________________ Von: mkgmap-dev <mkgmap-dev-bounces@lists.mkgmap.org.uk> im Auftrag von Mike Baggaley <mike@tvage.co.uk> Gesendet: Sonntag, 4. Februar 2018 15:14 An: 'Development list for mkgmap' Betreff: [mkgmap-dev] max-jobs patch
Hi Gerd,
Please find attached a patch that amends the default behaviour if the --max-jobs option is not specified, to using a value equal to the number of CPU cores, as suggested in a previous post. The documentation is also amended to reflect the change. This halves the execution time of mkgmap for building a map of Staffordshire on my 8-core PC when --max-jobs is not specified (I didn't know about this option previously and was unaware the performance could have been improved).
Cheers, Mike _______________________________________________ mkgmap-dev mailing list mkgmap-dev@lists.mkgmap.org.uk http://www.mkgmap.org.uk/mailman/listinfo/mkgmap-dev