Charm++ parallel programming system

[Phil Miller <mille121 AT illinois.edu>]

Hi Tom,

What version of Charm++ did you use in your attempt(s)? As noted in the linked document, the changes in Charm++ to support CrayPat are in our development line, but have not quite yet been released.

Our compiler wrapper 'charmc' has always called through the Cray compiler wrappers on Cray systems. If some component is missing or not working correctly, the problem lies elsewhere.

Looking through that document, there seems to be some skew introduced between the patch to Charm++ as Cray provided it, and what we ultimately integrated. On your Charm++ 'build' command line, you'll need to add the 'perftools' option like so to get all of the necessary compiler settings:

./build charm++ gni-crayxc smp perftools --with-production -g

This difference was introduced (I believe) out of concern for a potential negative performance impact of always applying the flags in question, since they reduce the number of CPU registers available to the compiler.

Also note the lack of 'craycc' option on that line - via Cray's CC, charmc will always use the compiler selected by the loaded PrgEnv-* module.

There may be some other discrepancies between the documentation provided by Cray and the current state of the various software components. Feel free to get back to us with further issues. In the meanwhile, I'll have someone on the Charm++ team walk through the entire process and see what other updates might need to be made.

--

Phil Miller

CTO, Charmworks Inc

On Thu, Jul 6, 2017 at 8:47 AM, Papatheodore, Thomas L. <papatheodore AT ornl.gov> wrote:

Hello. I am having trouble running CrayPat on a Charm++ example problem on Titan (Cray XK7) at ORNL. The error message that I encounter when trying to instrument the executable with pat_build is:

 

ERROR: Missing required ELF section '.note.link' from the program '/lustre/atlas2/csc198/proj-shared/tpapathe/test/charm-cuda/multicore-linux-x86_64-cuda/tests/charm++/simplearrayhello/hello'. Load the correct 'perftools' module and rebuild the program.

 

This error is usually caused by not having the perftools-base and perftools modules loaded before compiling a program. However, I compiled the program with these modules loaded and I still receive the message. I also recompiled Charm++ itself with these modules loaded, but still get the message. Is there anything special I need to do to get CrayPat to profile Charm++ applications? I found the Cray document (http://docs.cray.com/books/S-2802-10//S-2802-10.pdf), but this does not resolve my issue. Could it be that Charm++ compiles with charmc and CrayPat requires the Cray compiler wrappers (e.g. CC, ftn, etc.)?

 

Any help would be appreciated. Thanks.

 

-Tom