[mkgmap-dev] Performance of mkgmap.jar and splitter.jar

Sat Apr 4 10:16:44 BST 2009

I think during the last weeks the increased feature set of mkgmap is 
really nice, not so nice is the performance though.....
I made some tests - see below. I think with the current versions 
performance really has gone by the wayside. It takes 4times as long 
against austria.osm compared to rev 937.
I will check against some other versions to find out if there was one 
specific patch that fucked up the performance or if it increased slowly....
Compiling austria.osm (from geofabrik) with my custom style-files 
(6layers) takes 788 seconds with rev. 937, but 3519 seconds with rev 988.

1. Performance Tile Splitter.
Split austria.osm with already established areas.list (4 areas) takes 
120sec, the same but austria.osm.bz2 took astonishing 312 seconds. The 
tile splitter works significantly faster on unzipped sources.

2. Performance mkgmap rev 988 .gz zipped:
The bigger the tile size you try to get done in one step, the better the 
performance.

For tryout style1 calculating the 4 tiles took 6 minutes (about 1:30 
minute for tiles 1-3, and *3 minutes* for the last and biggest tile 
(which still works fine in Mapsource though). The same tiles trying to 
calculate with a bit more heavyweight (only lines though, no Polygons or 
POI) style2 - the first 2 tiles took a bit less than 1 minute each, the 
third (and only second biggest tile) took *15 minutes,* and the forth 
took 2:30 minutes. I don't know what causes mkgmap to fuck up here on 
the third tile. If someone wants to have a look at the exact 
configuration, I can send the configuration files (including batch to 
run it through). In total it took from *04:45 for the first style, but 
20:21 *for the second style.

2b) the same again this time from unzipped sources:
The first 3 tiles on stylefile1 got done in about 2 minutes, the fourth 
one took again 3 minutes. That's 04:42 compared to 04:45 zipped, so no 
significant difference).
The first 2 tiles on stylefile2 got done in about 1:20, the third now 
took 17 minutes and the fourth 2 minutes.(so even worse than before; 
thats 20:35 unzipped compared to 20:21 zipped)

The filesize of the resulting tiles with style1 is:
2.54MB
4.70MB
4.31MB
8.03MB

The filesize of the resulting tiles with style 2 is:
2.78MB
5.87MB
5.90MB
8.96MB

2c) trying to run the two styles on the whole austria.osm without 
splitting results in:
Stylfile1: 3:36:48 (so thats about a full minute quicker than the the 
country split into 4 tiles).
Stylefile2: 16:48 (that's about 4 minutes quicker, 4 tiles took 20:35).

2d) Speed of processing Austria.osm with mkgmap rev 937
Stylefile1: 2:52
Stylefile2: 3:17
*My whole mapset: 788 seconds (compared to 3519 seconds with rev 988)*

P.S. on a related note, in case the style-file is not found there should 
be an error message, and not a defaulting to the default mkgmap style.

P.P.S: see stylefile2, it's really short an simple - nothing else (no 
POI or Polygons), I have no clue why it takes so long on Austria.osm  
respectively tile three (having run splitter jar with 25000000).....
mtb:scale:uphill=0 [0x1d resolution 22]
mtb:scale:uphill=1 [0x1e resolution 22]
mtb:scale:uphill=2 [0x26 resolution 22]
mtb:scale:uphill=3 [0x29 resolution 22]
mtb:scale:uphill=4 [0x2b resolution 22]
mtb:scale:uphill=5 [0x1b resolution 22]
highway=primary         [0x04 road_class=0 road_speed=3 resolution 19]
highway=primary_link [0x04 road_class=0 road_speed=2 resolution 19]
highway=secondary     [0x05 road_class=1 road_speed=3 resolution 16]
highway=tertiary          [0x06 road_class=1 road_speed=4 resolution 20]
highway=residential     [0x07 road_class=1 road_speed=3 resolution 22]
highway=living_street  [0x07 road_class=1 road_speed=3 resolution 22]
highway=unclassified   [0x07 road_class=1 road_speed=4 resolution 22]

P.P.P.S - the commandline for mkgmap: "start java -jar -Xmx1184M 
d:\garmin\mkgmap_svn\dist\mkgmap.jar --description=02_Austria 
--style-file=2 --route --net --country-name=AUSTRIA --country-abbr=AUT 
--country-name=AUSTRIA --ignore-turn-restrictions --mapname=63260001 
austria.osm"
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.mkgmap.org.uk/pipermail/mkgmap-dev/attachments/20090404/d804d9cf/attachment.html 