Charm++ parallel programming system

[Jozsef Bakosi <jbakosi AT gmail.com>]

Hi folks,

I'm getting the following valgrind message only on Cray (no problem on, e.g., linux/mac):

==48771== Use of uninitialised value of size 8 

==48771==    at 0x21696E61: memcpy (memcpy.S:201)

==48771==    by 0x212E12E0: CkReductionMsg::buildNew(int, void const*, CkReduction::reducerType, CkReductionMsg*) 

==48771==    by 0x212EF68A: Group::contribute(int, void const*, CkReduction::reducerType, CkCallback const&, unsigned short)

This is from a chare group reduction of an array of doubles with CkReduction::sum_double.  There is a single memcpy() in src/ck-core/ckreduction.C:1501:

    memcpy(ret->data,srcData,NdataSize);

I am suspecting the memory size allocated behind srcData is smaller (by a single double) than NdataSize, probably because I'm feeding the wrong data size. The way I feed the data size to the contribute call is  via static_cast<int>( vec.size() * sizeof(double) ), and the data pointer is vec.data(), which I assume ends up being passed on to be srcData. Here vec is a std::vector<double>. I believe, this should be correct, but for some reason this is only a segfault on cray - valgrind does not even complain on linux or mac.

Does any have an idea how I can debug this?

Thanks,

Jozsef