<html><body style="word-wrap: break-word; -webkit-nbsp-mode: space; -webkit-line-break: after-white-space; "><div><div>On Aug 22, 2009, at 4:51 AM, Hermann Peifer wrote:</div><br class="Apple-interchange-newline"><blockquote type="cite"><p style="margin: 0.0px 0.0px 0.0px 0.0px"><font face="Lucida Grande" size="3" style="font: 12.0px Lucida Grande">Just to repeat my earlier observations: over the last days, I tried with all kinds of -wm and GDAL_CACHEMAX settings, and also added the options TILED=YES and SKIP_NOSOURCE=YES. I haven't documented the performance changes systematically, but my overall impression was that the changes were rather small. I also tried -multi on my dual processor machine, but I ended up with a fatal error.</font></p> </blockquote></div><div><br></div><div>In January 2009, working with GDAL version 1.6.0, I did some testing and documenting of the effect of <span class="Apple-style-span" style="font-family: Courier; font-size: 12px; ">GDAL_CACHEMAX<span class="Apple-style-span" style="font-family: 'Lucida Grande'; ">. <span class="Apple-style-span" style="font-size: medium; "><font face="Lucida Grande" size="3" style="font: 12.0px Lucida Grande">Using as input an uncompressed GeoTif 15,000 x 15,000 x 3 = 675 MB, organized into 1024 x 1024 tiles, I found that using gdal_translate to convert this GeoTif to a GeoJP2</font><font face="Lucida Grande" size="3" style="font: 12.0px Lucida Grande"> with the default </font><font face="Courier" size="3" style="font: 12.0px Courier">--config GDAL_CACHEMAX 40</font><font face="Lucida Grande" size="3" style="font: 12.0px Lucida Grande"> took 10473 sec (= 175 minutes), but increasing <span class="Apple-style-span" style="font-family: Courier; ">GDAL_CACHEMAX</span> by only 12.5% to </font><font face="Courier" size="3" style="font: 12.0px Courier">--config GDAL_CACHEMAX 45</font><font face="Lucida Grande" size="3" style="font: 12.0px Lucida Grande"> the processing took only 166 sec (= 2.7 minutes), which is 63 times faster! Further tests showed that increasing </font><font face="Courier" size="3" style="font: 12.0px Courier">--config GDAL_CACHEMAX</font><font face="Lucida Grande" size="3" style="font: 12.0px Lucida Grande"> to values greater than 45 (up to 1800) did not effect processing time. Greg</font></span></span></span></div><div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; font: normal normal normal 12px/normal 'Lucida Grande'; min-height: 15px; "><br></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Courier" size="3" style="font: 12.0px Courier">GDAL 1.6.0, released 2008/12/04</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Courier" size="3" style="font: 12.0px Courier">Input GeoTif 15,000 x 15,000 x 3 = 675 MB</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font face="Courier" size="3" style="font: 12.0px Courier">gdal_translate -of JP2KAK -co QUALITY=10 --config GDAL_CACHEMAX</font></div><div style="margin-top: 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><font class="Apple-style-span" face="Courier"><div>0040 10473.14 sec</div><div>0041 10326.75 sec</div><div>0042 10492.85 sec</div><div>0043 7081.57 sec</div><div>0044 3503.33 sec</div><div>0045 166.23 sec</div><div>0050 166.31 sec</div><div>0055 165.89 sec</div><div>0060 165.78 sec</div><div>0080 165.48 sec</div><div>0100 166.53 sec</div><div>0125 165.59 sec</div><div>0150 165.72 sec</div><div>0200 165.65 sec</div><div>0250 166.58 sec</div><div>0300 166.13 sec</div><div>0350 166.59 sec</div><div>0400 166.06 sec</div><div>0600 166.00 sec</div><div>0800 165.10 sec</div><div>1000 165.25 sec</div><div>1200 165.94 sec</div><div>1400 165.43 sec</div><div>1600 165.56 sec</div><div>1800 166.31 sec</div><div><br></div></font></div></div></body></html>