Parallel Computing

asm blocks


I am writing AVX code inside asm blocks (don"t want to use avx intrinsics).

A lot of gp registers are used and so they are mixed with the ones generated by the compiler and thus it is screwing the behavior of the code pretty fast.

Is there an automatic or manual way to avoid these register overlaps ?

Any link to documentation would be great.

I would like also to use asm blocks in fortan with ifort, but didn't find the way yet.



mic0: lost

Hi !

I begin with Xeon Phi and MPI. After a lot of troubles, yesterday I managed to run MPI programs on symmetric mode (both host and co-processor) as well as directly on mic0 after ssh.

But today I have troubles again.

MPSS starts correctly and 3 minutes later the status of mic0 is lost and I can not reset it.

Problem using DSS


I'm taking my first steps at MKL and after installation and linking libraries (I have Ubuntu 12.04, 64-bit) I tried to modify the direct solver dss_sym_c.c so that I could solve my sparse symmetric system which is stored in a binary file (1 based index). I changed CSR system but after that an unclassifiable error uccured at the "reorder step" of the program. What can be the reason of it?

Here's the code:

Запись в разрфженную матрицу и чтение из нее.

Добрый день. Есть ли в Intel MKL метод записи значения в разряженную матрицу? И соответственно чтение из нее. Нужно что-то типа такого:

sparseMatrix[1,3] = 0.012;

value = sparseMatrix[1,3];

Если есть, дайте пож-та пример, как такую разряженную матрицу инициализировать и работать с ней.


Заранее спасибо.


dgetrf performance drop above 10000


I'm doing performance testing using mkl composer_xe_2013_sp1.2.144 with the icc version 14.0.2 20140120 compiler and randomly generatoed matrices.

when the matrix size gets above 10000, I notice a performance drop of around 100GFlops ( size 9217 peforms wih 211GFlops but 10241 only has 109)

I tried using the align option to try aligning the data to 64 byte boundaries and this did offer a general speed up and reduced the drop to around 50GFlops but the drop is still there.

Access to previous versions of Intel MKL

I want to use DLL and Libs of Intel MKL version in my software program. If I purchase a license copy of latest version of Intel MKL for example 11.0, then do I get access to previous version i.e.

Please let me know if any body knows about this. Thank you in advance.

Run Intel MPI without mpirun/mpiexec


I am wondering does Intel MPI support a MPI run without mpirun/mpiexec in the command line?

I know that in MPI-2 standard, it supports the “dynamic process” feature, i.e., dynamically generate/spawn processes from existing MPI process.

What I am trying to do here is 1) Firstly, launch a singleton MPI process without mpirun/mpiexec in the command line; 2) Secondly, use MPI_Comm_spawn to spawn a set of process on the different host machines.

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