Re: [Boost-users] boost MPI issue on windows

Subject: Re: [Boost-users] boost MPI issue on windows
From: Nick Collier (nick.collier_at_[hidden])
Date: 2010-10-26 09:52:30

I winnowed my own code down to a simple scatter call. I get the error under release mode but not under debug. Here's the code:

namespace mpi  = boost::mpi;
int main(int argc, char **argv) {
        mpi::environment env(argc, argv);
        mpi::communicator world;

        vector<int> out;
        vector<vector<int> > in;
        if (world.rank() == 0) {
                for (int i = 0; i < world.size(); ++i) {
                        vector<int> vec(10, 12);
                        in.push_back(vec);
                }
        }

        try {
                mpi::scatter(world, in, out, 0);
        } catch (std::exception& ex) {
                std::cerr << ex.what() << std::endl;
                throw ex;
        }

        cout << world.rank() << " : " << out.size() << endl;
}

And the error is:

ar size: 4293462132
MPI_Send: Invalid count, error stack:
MPI_Send(176): MPI_Send(buf=0x0016F78C, count=-1505164, MPI_PACKED, dest=1, tag=
2147483647, MPI_COMM_WORLD) failed
MPI_Send(101): Negative count, value is -1505164

MPI_Alloc_mem: Invalid argument, error stack:
MPI_Alloc_mem(119): MPI_Alloc_mem(size=-1505164, MPI_INFO_NULL, baseptr=0x003EF6
8C) failed
MPI_Alloc_mem(82).: Invalid value for size, must be non-negative but is -1505164

thanks,

Nick

On Oct 26, 2010, at 2:58 AM, Matthias Troyer wrote:

> Hi Nick,
> 
> On 26 Oct 2010, at 00:52, Nick Collier wrote:
> 
>> Sorry for not getting back sooner, and thanks for the initial reply. I added a print to packed_archive_send, so it now looks like:
>> 
>> void
>> packed_archive_send(MPI_Comm comm, int dest, int tag,
>>                     const packed_oarchive& ar)
>> {
>> 	std::cout << "ar size: " << ar.size() << std::endl;
>>   const void* size = &ar.size();
>>   ....
>> 
>> When I run this under release mode I with, I get:
>> 
>> ar size: 4265919640
>> 
>> MPI_Send: Invalid count, error stack:
>> MPI_Send(176): MPI_Send(buf=0x01E8AE18, count=-29047656, MPI_PACKED, dest=1, tag
>> =2147483647, MPI_COMM_WORLD) failed
>> MPI_Send(101): Negative count, value is -29047656
>> 
>> When I run it under debug mode, I don't get the error and 
>> 
>> ar size: 1622.
>> 
>> Any suggestions how to proceed are much appreciated. 
> 
> This seems to point towards either a bug in your code, that you overwrite the memory location of the packed_oarchive, or a bug in the optimizer. Can you try a simple test program where you are sure that you don't write out of bounds anywhere?
> 
> You could also try to see what goes on by adding more output statements to the size() function of packed_oprimitive, or add a size function to packed_oarchive that prints internal_buffer_.size() and then calls the size function of the packed_oprimitive base class. It seems that either the internal_buffer_ vector is messed up, or the reference in the base class by either a compiler bug o a bug in your code.
> 
> Matthias
> 
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