Intel® oneAPI Math Kernel Library
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One more data race threading issue in zgetrf (10.3 update 5)

AndrewC
New Contributor I
156 Views
MKL 10.3 update 5 has made many strides over previous versions in fixing data races in multi-thread applications. I run tests on my code under Intel Inspector XE , and the data races inside MKL are almost gone
... EXCEPT for this one that keeps cropping up. I do not believe it is a "harmless" data race. They never are...

This needs to run with OpenMP on, obviously.
ID Problem Sources Modules State
P1 Data race testzgetrf.cpp testzgetrf.exe New

The actual data race (write) is at this location.

mkl_core.dll!mkl_serv_deallocate - mkl_core.dll:4937
testzgetrf.exe!zgetrf - testzgetrf.exe:6101
testzgetrf.exe!test - testzgetrf.cpp:27





[cpp]#include "mkl_lapack.h"
#include 
void test()
{
#define NSIZE 20
		#pragma omp parallel for
		for( int iLoop=0;iLoop<20;iLoop++){
			MKL_Complex16 a[NSIZE][NSIZE];
			for( int i=0;i.real=1;
						a.imag=0;
					}else{
						a.real=0;
						a.imag=0;
					}
				}
			}
			int M = NSIZE;
			int N = NSIZE;
			int info;
			int ipvt[NSIZE];
			zgetrf(&M, &N, (MKL_Complex16 *)a, &M, ipvt, &info);
			//std::cout << info << std::endl;
		}
}

int main(int argc, char * argv[])
{
	test();
	return 0;
}

[/cpp]

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7 Replies
yuriisig
Beginner
156 Views
MKL_Complex16a[NSIZE][NSIZE];??????????
AndrewC
New Contributor I
156 Views
And your point is what?
yuriisig
Beginner
156 Views
It is an one-dimensional array.
AndrewC
New Contributor I
156 Views
zgetrf expects a NxM matrix of complex double.
It declares a block of memory that can be though of as a one-d array [NSIZE*NSIZE] or a 2D array [NSIZE][NSIZE], lapack does not care how you declare your memory as long as the layout is column major, and since my array is square that is not an issue.


yuriisig
Beginner
156 Views
Very interesting. I did not know it. Tell explicitly as storage for a two-dimensional array is selected.
This selection of storage depends on the translator?
AndrewC
New Contributor I
156 Views
Is this a Turing test? And way off-topic
yuriisig
Beginner
156 Views
I hinted that you are mistaken. Consider an example of the fragmented storage.
Reply