<span><br></span><blockquote style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;" class="gmail_quote"><blockquote><span>Date: Mon, 21 Aug 2006 17:53:53 +0100</span><br><span>From: Andrew Larcombe <
<a href="mailto:andrew@andrewlarcombe.co.uk">andrew@andrewlarcombe.co.uk</a>></span><br><span>Subject: Re: [Gdal-dev] ECW compression - Extremely slow Linux</span><br><span> performance - POSSIBLE HACKISH SOLUTION
</span><br><span>To: <a href="mailto:gdal-dev@lists.maptools.org">gdal-dev@lists.maptools.org</a></span><br><span>Message-ID: <44E9E521.7000304@andrewlarcomb</span><br><span><a href="http://e.co.uk">e.co.uk</a>></span>
<br><span>Content-Type: text/plain; charset=ISO-8859-1; format=flowed</span><br><span></span><br><span>Initial testing appears to show that running ECW conversion from</span><br><span>gdal_translate in FWTools under the windows non-emulator, WINE, is
</span><br><span>6xfaster than running it natively. I'm now getting translation times of</span><br><span>around 10 seconds, rather than 60 seconds on my laptop. I can only</span><br><span>assume wine's multithreading is less crippled than that provided by
</span><br><span>ERMapper?</span><br></blockquote><span></span></blockquote><div><div><br>We moved to a WINE based solution for stability and found the same performace gain.<br><br>In addition to being extremely slow in the Linux version, it's also quite buggy. Apparently the ERMapper folks really don't understand the posix threading model. We can limp along for a while in a single threaded app before crashing. But calling any ECW decode routines from a multithreaded app running on a multiprocessor machine (even if all the calls are made from a single thread) causes all kinds of corruption of IO data structures and crashes quite quickly. I haven't been able to get the ERMapper folks to be any more specific than "Yes, we have some threading problems on Unix. We're looking into it.".
<br><br>Once we tried the WINE solution we also noticed the speedups.<br><br>Enjoy your WINE. :-)<br><br></div></div>