[Gdal-dev] Will increasing the RAM on a server increase the speed of gdalwarp?

[Frank Warmerdam]

John Mitchell wrote:
> Frank,
> 
> Thanks for the recommendation of adding --config GDAL_CACHEMAX 500 -wm 
> 500 to the gdalwarp command.
> 
> With --config GDAL_CACHEMAX 500 -wm 500 added to gdalwarp the speed of 
> mosaicing 6 tiles creating a mosaic of 3 gb on a server with 4 gb of RAM 
> increased the gdalwarp speed by 25%.
> 
> I then tried --config GDAL_CACHEMAX 625 -wm 625 instead of --config 
> GDAL_CACHEMAX 500 -wm 500 and I got the following error:
> Out of memory allocatint 400042260 byte destination buffer
> 
> If the RAM was increased beyond 4 GB then I would be able to increase to 
> GDAL_CACHEMAX 625 -wm 625 and beyond, but you don't believe that above 
> 500 will have any effect on gdalwarp performance.  Correct?

John,

I believe you are well into the law of diminishing returns.  But to
verify this, try comparing performance with 500 and with 400MB, to see
if going from 400 to 500 actually is helping noticably.

Best regards,
-- 
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