Threading on Intel® Parallel Architectures

Get some problem with global variable declaration

I try use an Intel PHI co-prococessor.But i got some problem with global variable declaration .I decline A,B,C as global variable.But the value of them are equal。Turn out to be,A=5,B=5,C=5.And AA=30.The right AA must be 17.Try to get some help here.Thanks.


#include <stdio.h>
#include <math.h>
#include <omp.h>
#pragma offload_attribute(push,target(mic))
float *A;
float *B;
float *C;
#pragma offload_attribute(pop)

//__attribute__((target(mic))) float *A,*B,*C;

Parallel Image Processing in OpenMP - Image Blocks

I'm doing my first steps in the OpenMP world.

I have an image I want to apply a filter on.
Since the image is large I wanted to break it into non overlapping parts and apply the filter on each independently in parallel.
Namely, I'm creating 4 images I want to have different threads.

I'm using Intel IPP for the handling of the images and the function to apply on each sub image.

I described the code here:

linking with two versions of mkl (multi threaded and single threaded) in one application


Is it possible to use both the single threaded version of mkl library and the multi threaded version of mkl in one application?

I need the single threaded version to use with PLASMA library, yet at some other part of my code, I need use mkl PARDISO, for which I need the multi threaded version.

Any help will be greatly appreciated.




Memory to CPU (mov) bandwidth limitations

(sorry for weak english I am not native english, Not sure if right forum, first time here - This is general about some hardware limits i do not understand technical reason and I would very like to know)

We have now parallelised SIMD arithmetic (like 8 float mulls or divisions in one step) theoretical (but also nearly practical) arithmetical bandwidth per core is thus like 4GHz * 8 floats = about 30 GFLOPS per core or something like that

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