[geos-devel] JTS/GEOS performance

[strk at refractions.net]

Some time ago I've been researching about GEOS performance
problems as related to JTS. Attached is a shapefile and an .xml
test you can use to compare the two.

JTS does not support buffers tests, so you'll need to use another
method for that. I used JUMP, which reports computation time.

Well. The operation is a buffer(polygon, 2000).

 JTS:  18 seconds
GEOS: 574 seconds (9 minutes, 34 secs)

GEOS computation keeps the CPU pretty busy (98.2-99.8%)
and takes up to about 170 MB of ram

JTS seems to use 3 threads, the bigger using at most 80% 
of CPU, but most of the time far below that point.
JUMP reports 104MB committed, but I'm not sure about the meaning.

For GEOS, valgrind reports (with buffer 500):
 malloc/free: 2982697 allocs, 2982697 frees, 924407212 bytes allocated.

How much do you think this wild allocation negatively influence the
poor performance of GEOS ?

--strk;