[Insight-developers] itk performance numbers

[Rupert Brooks]

Brad,

So Mattes MI metric, single threaded, was 4 times slower in 4.2, and after
the patch became only 2 times slower.  Egad - thats a big difference - i
dont know about you but i am quite surprised.  I wasnt using this metric so
i hadn't noticed.  On friday I went compared the files from 3.20 -> 4.2
briefly, but I didnt see where the slowdown would be.

It does not seem to be in the interpolators - i made an interpolator
benchmark and it seems to run as good or better in 4.2.  I split itkbench
into multiple files for each benchmark to try to stay organized.  I'll try
to reproduce your result from your fork and pull it in.

In any case, i think your approach to handling the Jacobian is good.  Since
the Jacobian is used by nearly all metrics, i wonder if it should be a
member of the base class and allocated there?

Cheers,
Rupert

--------------------------------------------------------------
Rupert Brooks
rupert.brooks at gmail.com



On Fri, Jul 27, 2012 at 9:59 AM, Bradley Lowekamp <blowekamp at mail.nih.gov>wrote:

> OK here are some more numbers for the latest patch in gerrit. I will
> follow Ruperts format as it's the most clear.
>
> MeanSquares:
> Threads 3.2 4.2 4.2+patch patch percentage of 3.20
> 1 0.3615 0.8214 0.4071 113%
> 2 0.3222 0.6055 0.3365 104%
> 4 0.3249 0.4448 0.3293 101%
> 8 0.1703 0.3093 0.1943 114%
> 12 0.1457 0.2031 0.1322 91%
> 24* 0.1062 0.1332 0.0949 89%
>
> MutualInformation:
> Threads 3.2 4.2 4.2+patch patch percentage of 3.20
> 1 0.1467 0.6103 0.3353 228%
> 2 0.1036 0.3747 0.1774 171%
> 4 0.0847 0.2175 0.1262 149%
> 8 0.0655 0.1291 0.0681 104%
> 12 0.0551 0.1035 0.0486 88%
> 24* 0.0460 0.0829 0.0526 114%
>
> *Hyperthreading
>
> The observation to be made about MutualInformation is that while 4.2 it's
> still slower with one thread, there is a significant increase is speed-up
> due to threads now.
>
> Brad
>
> On Jul 26, 2012, at 2:02 PM, Rupert Brooks wrote:
>
> Ok that makes way more sense, sorry i didnt understand first time around.
>
> Just so i've got it right
> Threads                    3.20                              4.2+patch
>        Time 4.2 as percent of 3.20
> 1                         0.347567                            0.383342
>            110.293%
> 2                         0.300869                            0.335328
>            111.453
> 4                         0.348677                            0.315688
>             90.5388
> 8                         0.182681                            0.192132
>            105.173
>
> So theres about 10% more time with ITK 4.2 used in the 1 and 2 thread
> case.  That is definitely better than what we were getting.  Cool.
>
> Rupert
>
> --------------------------------------------------------------
> Rupert Brooks
> rupert.brooks at gmail.com
>
>
>
> On Thu, Jul 26, 2012 at 1:13 PM, Bradley Lowekamp <blowekamp at mail.nih.gov>wrote:
>
>> Sorry for not being clear! I got too excited by finding the solution to
>> the performance issue with ITKv3 registration in ITKv4.
>>
>> This first is vanilla 3.20, the second is 4.20+ the gerrit patch. The
>> third is the gerrit patch with the pre-malloc of the Jacobin outside the
>> threaded section! Vanilla 4.2 is ~2x 3.20 for this test on my system too.
>>
>> Summary for the MeansSquares metric in your test:
>>
>> 3.20:  1X
>> 4.2: 2+X
>> 4.2+gerrit patch: 1X
>> 4.2+gerrit patch + single-threaded preallocation of jacobian: 1.5X
>>
>
> ========================================================
>
> Bradley Lowekamp
>
> Medical Science and Computing for
>
> Office of High Performance Computing and Communications
>
> National Library of Medicine
>
> blowekamp at mail.nih.gov
>
>
>
>
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