Hi Gerd, please find attached v2 of the max-jobs patch. This version additionally catches out of heap memory exceptions and displays a message suggesting either the use of the Java -Xmx option to increase the available heap memory or the mkgmap --max-jobs option with a smaller value to reduce the memory requirement (the latter is suggested only if using more than one thread).
How does that seem? Regards, Mike -----Original Message----- From: Gerd Petermann [mailto:gpetermann_muenc...@hotmail.com] Sent: 05 February 2018 07:28 To: Mike Baggaley <m...@tvage.co.uk>; 'Development list for mkgmap' <mkgmap-dev@lists.mkgmap.org.uk> Subject: Re: [mkgmap-dev] max-jobs patch 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-boun...@lists.mkgmap.org.uk> im Auftrag von Mike Baggaley <m...@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
maxjobs-v2.patch
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