[petsc-users] (no subject)

[Karl Rupp]

Hi,

 >    Im a masters student from Indian Institute of Technology delhi. Im
> working on PETSc.. for performance, which is my area of interest. Can
> you please help me in knowing 'How to run PETSc on MIC' .    That would
> be of great help to me.

my experience is that 'performance' and 'MIC' for bandwidth-limited 
operations don't go together. Regardless, you can use ViennaCL by 
building via
  --download-viennacl
for using the MIC via OpenCL, but you are usually much better off with a 
proper multi-socket CPU node.

Feel free to have a look at my recent slides from the Intl. OpenCL 
Workshop here:
http://iwocl.org/wp-content/uploads/iwocl-2014-tech-presentation-Karl-Rupp.pdf
PDF page 32 shows that in the OpenCL case one achieves only up to 20% of 
peak bandwidth for 1900 different kernel configurations even for simple 
kernels such as vector copy, vector addition, dot products, or dense 
matrix-vector products. With some tricks one can probably get 30%, but 
that's it.

PETSc does not provide any 'native' OpenMP execution on MIC for similar 
reasons.

Best regards,
Karli