[Gdal-dev] Performance of MrSID support in GDAL

[juergen.link at freenet.de]

Hi Folks,
we are facing a strange problem using UMN Mapserver with MrSID support.
When asking for raster data from a compressed source the mapserver on our fast Linux box 
takes about 4.5 seconds to decode MrSID data. A much smaller and slower Windows box
does the job in less than a second.
We cooked down the problem and found 2 possible hints:
- LizardTech's  tool mrsiddecode takes about 0.5 sec to render a JPEG file 
      mrsiddecode -i 0259005590_dop5__c_025.sid -o test.jpg -ulxy 500 500 -wh 800 600
- while gdal's tool  takes 4.5 sec
      gdal_translate 0259005590_dop5__c_025.sid test_gdal.jpg -srcwin  500 500 800 600 -of JPEG
So it seems to be a lack of gdal lib, rather  than mapserver's?
Did we do any wrong with our compile job??

Thanks in advance
Jürgen


Details:
- SUSE Linux  Enterprise (SLES 9)
- gdal 1.2.5
- LizardTech's DSDK (Geo_DSDK-4.0.9.713)
- gcc version 3.3.3
- gdal configure options:   --with-mrsid=/opt/LT/Geo_DSDK-4.0.9.713 --without-mysql --with-oci=/opt/oracle/OraHome1/

The compressed raster data can be found at mapbender's project home at sourceforge:
      https://sourceforge.net/project/showfiles.php?group_id=88554&package_id=118698&release_id=301127