[mkgmap-dev] [PATCH v10] make maps in parallel

Tue May 19 11:01:09 BST 2009

Mark Burton wrote:
> Changed default number of threads to be 1. If you specify --max-jobs
> without a value, you get one thread per core. --max-jobs=N means use N
> threads.
> 
> With regard to comparing the output with known good maps to see if the
> parallel processing is corrupting anything, one problem is that the
> files contain timestamps. I have test code that zeros the time stamps
> and have been able to compare the output from different runs.
> 

I have just run this against todays great_britain.osm and using
--max-jobs I had a runtime of 397s and without was 676s. This is on my
dual core laptop with 4GB RAM. The 2 files created had exactly the same
number of bytes and in my admittedly very brief and not overly
scientific testing intertile routing seems to be the same for both. I
haven't dug any deeper than that though as I'm meant to be working :)

Paul