[geos-devel] CPU buildup with repeated operations

thep t.burt at virgin.net
Sat Mar 7 09:27:11 EST 2009

Hi, thanks for your response & ruling out denormalization. My program does
have a tiny memory leak, but it isn't necessarily within this code, and the
relative memory usage hardly increases after the CPU usage starts
increasing, so I don't think there's much swapping going on...

If it's not a memory issue, is there any possibility of non-destroyed
created objects taking up cpu time, even if I'm not doing any operations on


Mateusz Loskot wrote:
> thep wrote:
>> Hi, am having a problem with a system built using GEOS, wondering if
>> anyone
>> could help. Am using GEOS to generate sound and graphics from geom
>> operations in realtime. If I do a constant amount of work (e.g. roughly
>> 150
>> binary operations per second)  then gradually my CPU usage builds up,
>> until
>> after about 5 minutes, it becomes unusable. This is whilst carrying out
>> the
>> same amount of operations. 
>> Am using the C API on an Intel Core 2, can anyone think what this might
>> be?
> What is memory usage? Does it increase significantly?
> Chances are that if your program uses a lot of memory
> then your system starts swapping, what uses CPU time quite a lot too.
>> As far as I'm aware I'm destroying all objects after each set of
>> operations,
>> but if I've missed one (and therefore have a constantly increasing number
>> of
>> objects), does GEOS perform any housekeeping on created objects which
>> could
>> cause this CPU buildup?
> I'd suggest to check if your program does proper cleanup, run it through
> valgrind and check for memory leaks.
>> The other thing I've considered is could it be an
>> Intel denormalization issue? 
> I'm not sure about that, but AFAIK this problem applies only to P4 and
> prior CPUs from Intel CPUs. But you are using their successors actually.
> Anyway, you may want to confirm this in Intel docs.
> Best regards,
> -- 
> Mateusz Loskot, http://mateusz.loskot.net
> Charter Member of OSGeo, http://osgeo.org
> _______________________________________________
> geos-devel mailing list
> geos-devel at lists.osgeo.org
> http://lists.osgeo.org/mailman/listinfo/geos-devel

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