[Insight-users] Performance regression ImageSeriesReader? (with test)

[Bill Lorensen]

Brad,

It looks like the meta data array is populated in both the
GenerateOutputInformation and GenerateData. Also all slices are
processed in GenerateOutputInformation. In 2.8, only 2 slices were
processed.

Why were these changes made? We are also seeing bad dicom performance
in Slicer3.

Bill

On Mon, Mar 22, 2010 at 6:24 AM, Bradley Lowekamp
<blowekamp at mail.nih.gov> wrote:
> Hello,
> Can you please tell us a little more about your test data and computer. What
> kind of file system is the data on ( locale or network)? How much memory
> does the computer have? What is the size of the data? What is the native
> pixel type of the data? What are the actual timings? Does the execution seem
> to be CPU or IO bound?
> One of the changes that was made to the class was to populate the
> MetaDataArray in the UpdataOutputInformation phase of the instead of the
> UpdateOutputData part. This should be just reading the headers of the files
> in the series. There were several reasons this change was made. To help
> determine the cause of your slowness, lets break up the timing a little
> further.
> Could you please call:
> start timer
> reader->UpdateOutputInformation();
> lap timer
> reader->UpdateLargestPossibleRegion();
> stop timer
> And post the timing results.
>
> Thanks,
> Brad
> On Mar 21, 2010, at 2:52 PM, Roger Bramon Feixas wrote:
>
> This week we updated our ITK version from 2.8 to 3.16  and we noticed the
> medical models are loading 2x slower using the 3.16 ITK version. We use
> itk::ImageSeriesReader and the problem is focused in its Update() method.
> I attached a simple test program which reproduces the problem and where we
> can see that the Update() method is 2 times slower using ITK 3.16 vs. ITK
> 2.8.
> We compiled both versions using Visual Studio 2008 on Windows XP 32bits and
>  we don't known if this problem also occurs in other platforms.
> I wonder if other itk users have this same performance problem and if there
> is anybody can help us in order to solve it.
> Thanks!
>
> Roger
> <test.zip><ATT00001..txt>
>
> ========================================================
>
> Bradley Lowekamp
>
> Lockheed Martin Contractor for
>
> Office of High Performance Computing and Communications
>
> National Library of Medicine
>
> blowekamp at mail.nih.gov
>
>
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