[Gdal-dev] ECW compression - Extremely slow Linux performance

[Frank Warmerdam]

Andrew Larcombe wrote:
> Hi,
> 
> I'm using gdal_translate to convert a 4000px x 4000px uncompressed 46MB 
> tiff to an ECW file.
> 
> On a Windows XP laptop (Pentium M 1.6 GHz, 512MB RAM) using the latest 
> fwtools download the process takes about 6 seconds.
> 
> On a RedHat Enterprise 3 powered Quad-3.8Ghz processor with 2GB ram 
> using gdal-1.3.1 built from source the process takes ~120 seconds.
> 
> In each case the command used is as follows:
> 
> gdal_translate -of ECW -co "TARGET=90" OSIM_TQ3517_2004-07-07.tif test.ecw
> 
> Does anyone have any thoughts on why their is such a considerable 
> difference in speed, and what I can do to remedy the situation?

Andrew,

Have you watched the CPU usage to see if it is 100% on the linux system
when doing the compression?  If not, then I *suspect* some sort of thread
switching latency or something similar.

Best regards,
-- 
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I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
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