Could you please post the datasets you are using, initial level set etc..<br><br>It would be best if you could try on the dataset available in the following paper, from which the parallel sparse field is implemented. They report a near linear speedup until 15 processors or so,<br>
<br><cite><a href="http://www.cs.utah.edu/research/techreports/2005/pdf/UUCS-05-002.pdf">www.cs.utah.edu/research/techreports/2005/pdf/UUCS-05-002.pdf</a><br><br><br></cite><br><div class="gmail_quote">On Sun, Feb 15, 2009 at 3:33 PM, Brady McCary <span dir="ltr"><<a href="mailto:brady.mccary%2BITK@gmail.com">brady.mccary+ITK@gmail.com</a>></span> wrote:<br>
<blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">insight-users,<br>
<br>
I have done some superficial profiling of a level set method using<br>
ParallelSparseFIeldLevelSetImageFilter. The results are as follows:<br>
<br>
1 Thread(s)<br>
real 12m0.678s<br>
<br>
2 Thread(s)<br>
real 20m51.607s<br>
<br>
3 Thread(s)<br>
real 18m27.440s<br>
<br>
4 Thread(s)<br>
real 17m2.819s<br>
<br>
5 Thread(s)<br>
real 15m57.489s<br>
<br>
All runs were exactly the same except for the NumberOfThreads argument<br>
to the filter. As you can see, I am experiencing a penalty for<br>
multithreading. I have not tested more than 5 simultaneous threads,<br>
but I will test 6, 7, and 8 threads this week when the hardware is<br>
available to me. If the trend continues, then probably around 7 or 8<br>
threads I will benefit from multithreading.<br>
<br>
However, this is contrary to my reckoning, and my computation should<br>
scale (mostly) linearly with the number of threads. I would like to<br>
discover the culprit. Would someone familiar with this filter<br>
recommend a general course of action?<br>
<br>
For posterity, some keywords: thread, profile, gprof.<br>
<br>
Thanks,<br>
<br>
Brady<br>
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</blockquote></div><br><br clear="all"><br>-- <br>Karthik Krishnan<br>R&D Engineer,<br>Kitware Inc.<br>Ph: 518 371 3971 x119<br>Fax: 518 371 3971<br>