Slow inter-image data transfer using coarrays

[Chris_G_2]

I am using coarrays with the Intel Fortran compiler (2011) with Windows 7, 64 bit. Transferring large matrices (200x2000) between images is taking several (>5) seconds. Is this a well known phenomenon? Is the data transrerred a byte at a time? Simple code to emulate this problem is enclosed.

Chris

[Steven_L_Intel1]

We are working on improving the performance of coarrays. Some of this work is included in Update 1 to the 2013 edition, but requires adding the undocumented command line option /switch:coarray_opts It will be the default in a future version. When I used this, the time taken for your program on 8 images dropped from 97 seconds to 25.4 seconds.

[Chris_G_2]

Thanks, as always. I have ordered the 2013 version and it will arrive soon. Is Update 1 available to download? Chris

[Steven_L_Intel1]

Yes, Update 1 was released a few weeks ago. Once you get your serial number you can register it at https://registrationcenter.intel.com/ and download the latest version.