Non-square Matrix Transpose

Hi guys,

Are there any highly optimized MKL routines or maybe performance primitives that can do rectangle matrix transposition but without scaling?

I've been using mkl_omatcopy but it seems to perform worse than a normal baseline implementation and I suspect this is due to the additional scaling that is performed. I've attached a plot running a naive baseline implementation with comparison on omatcopy and imatcopy. The latter I know runs very poorly on non-square matrices. 

I just want to know whether I should start spending some time optimizing my own transpose routine with AVX/AVX2 and blocking or whether there's a very efficient one out there already. 

Also, swapping indices is not viable for what I am trying to achieve. 

Thank you in advance!

Ioan