MKL 11 Versus MKL 10 Performance

MKL 11 Versus MKL 10 Performance

I have a benchmark application that mainly does two types of things:

* FFTs

* Eigenvector decompositions

In both cases, the new MKL11 benchmarks much slower than MKL10 on a I7 IVY Bridge, Sandy Bridge and other CPUS.

For the Eigenvector code, it is about 1/2 the performance in version 11.  For the FFTs the performance is degraded by about 30%.

Is there a reason why MKL 11 performs worse?  Is there something I need to do to at least get equivalent performance to MKL 10?

Thanks for your assistance in advance.

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could you please a sample code show this performance problem?  Also let us know 1)how code is linked 2) Is it a 32 bit code or Intel64 code 3) Windows/Linux?


I have attached a complete VS2008 project which demonstrates the problem.  Press the "EigenValues" button and  "Run Benchmark" buttons to see the performance.  As a correction the FFT times are improved in version 11 BUT the eigenvalue calculation times are substantially worse under version 11.  Here is a summary of measured benchmarks:


  I7-920 32Bit MKL10: 1.3 Seconds; I7-920 32Bit MKL11: 2.53 Seconds; I7-920 64Bit MKL10: 1.09 Seconds; I7-920 64Bit MKL11: 1.65 Seconds

 I7-3770 32Bit MKL10: .757 Seconds; I7-3770 32Bit MKL11: 1.4 Seconds; I7-3770 64Bit MKL10: .63 Seconds, I7-3770 64Bit MKL1: .98 Seconds

In order to compile, you copy the noted (in .txt file) .lib files into the folders for libraries by the way.


So the mystery is: why is MKL11 substantially worse in performance for Eigenvector decompositions compared to MKL 10.


I sent the project and source code as an attachment, but I dont see it in the chat.  Is there some magic I need to do to get the attachment uploaded?  Should I email it somewhere?

>>...I sent the project and source code as an attachment, but I dont see it in the chat...

Why wouldn't you add a zip-file with the test project to a new post in the current thread?

In that case everybody will be able to test, if interested. As soon as you add the zip-file press 'Start upload' button and as soon as download completed press 'Submit' button.

Note: There is a little problem. A developer should have MKL v10 and MKL v11 installed on its computer. I don't have MKL v10, for example.

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