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Pascal, Ipp vs. MKL: Depends on the vector or matrix sizes. MKL is designed for large vectors/matrices. It ramps up to near peak for dgemm around 128-256 elements ( N=M=K ). So for smaller matrices you will probably see as good/better/similar performance from IPP. The performance curves vary by BLAS routine. Generally, though, MKL should have 128 element vectors/matrices to amortize the startup costs. Icc vs. ifort: depends on the program. If a C programmer avoids pointer-based arrays and avoid aliasing, then the performance should be similar. That is to say, if you program C like a Fortran programmer then it should be close to as fast as ifort. Generally, though, Fortran is faster. This can be a rather religious argument: you can program well in either language, and you can write bad, slow programs in either language. Fortran compilers generally are able to extract more performance since aliasing is very limited whereas in C pointers cause fits for optimizers. For Core 2 Duo, try these options with both compilers: -O3 -xT -ipo as a starting point. Fortran matmul vs MKL. MKL will outperform matmul when matrices have 128 elements for more. Below that, hard to say. I'd be curious to find out. For MKL, set env var OMP_NUM_THREADS equal to the number of cores in your system. It is internally threaded and will parallelize the operations. However, if your code is parallelized you will want to run MKL single-threaded by setting OMP_NUM_THREADS=1. you do not want to oversubscribe your cores. ron -----Original Message----- From: fortran-dev-bounces+ronald.w.green=email@hidden [mailto:fortran-dev-bounces+ronald.w.green=email@hidden] On Behalf Of p666 Sent: Wednesday, December 20, 2006 4:58 PM To: email@hidden Subject: mkl versus ipp hello, does anyone know if the mkl is the same performance as ipp on common functions, for instance matrix related operations ? also does anyone know if a icc program is the same performance as a ifort program provided they link on the same mkl routines ? and finally is the matmul fortran routine of ifort slower that the mkl matrix multiply function ? in short is intel fortran faster than intel c (on core 2 duo) with the common mkl/ipp library ? thanks in advance pascal _______________________________________________ Do not post admin requests to the list. They will be ignored. Fortran-dev mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: l.com This email sent to email@hidden _______________________________________________ Do not post admin requests to the list. They will be ignored. Fortran-dev mailing list (email@hidden) Help/Unsubscribe/Update your Subscription: This email sent to email@hidden
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