[mkgmap-dev] [PATCH v6]splitter memory usage

Fri Nov 18 16:45:54 GMT 2011

Does adding -Xms also add performance on systems with abundant memory?

On 18.11.2011 17:00, GerdP wrote:
> Hello list,
>
> thanks for the comments reqarding patchv5.
> Attached is one more patch to be applied against the branch.
> Changes:
> - Enhanced dictionary size to 65535
> - Avoid allocating chunks (short[] objects) with a size that is not a
> multiple of 8 (r189 wasted 4 bytes for each chunk)
> - introduced special code for one-value-chunks
> - max-areas=255 is the default again, but maximum allowed is now 2048
>
> I did not find a simple way to allow also "auto" for the parameter
> optimize-mem. Maybe Steve or WanMil can help? auto should set
> optimize-mem=true if Runtime.getRuntime().maxMemory()<  2GB
>
> Remarks regarding performance:
> On WinXP systems, use java -Xms1600m -Xmx1600m -jar splitter.jar ...
> On 64bit boxes use also -XX+UseCompressedOops
> This avoids a lot of GC work. I did not yet try that with very large files
> like europe.osm.pbf.
> http://gis.638310.n2.nabble.com/file/n7008720/memory_patch_v6.patch
> memory_patch_v6.patch
> Some numbers for splitting germany.osm.pbf:
> patchv6 with -Xms and optimize-mem=true: 588s
> patchv6 with -Xms and optimize-mem=false: 594s
> patchv6 without -Xms and optimize-mem=true: 651s
> patchv6 without -Xms and optimize-mem=false: 622s
>
> r189 without -Xms and optimize-mem=false: 639s
>
> --
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