Project details here.
This project implements collective operations for UPC++ using single-sided communications. The project is 'header-only'. Serialization routines are third-party provided and will require a user application to link to a library and a compile-time-flag to tell the header files which serializer to utilize.
Boost Software License
- Broadcast
- Scatter
- Gather
- Reduce
- binomial tree
- binary tree
- UPC++
- Boost Serialization or STE||AR HPX Serialization
The implementations specifically targets log2 nodes and data set sizes. Any C++ container type providing iterator support can be used with this library.
The implementation depends on using the following datatype to control communications:
upcxx::dist_object< std::tuple< std::int32_t , std::string > > args;
args is exposed to the global address space. std::get<0>(args) returns a std::int32_t that is used as a mutex for a spinlock. The spinlock code looks like this:
upcxx::progress();
while(!atomic_xchange( &std::get<0>(*args), 1, 0 )) {
upcxx::progress();
}
the calls to upcxx::progress() clear the active message queues and allow remotely invoked asynchronous functions to execute. std::get<1>(args) returns the communication data buffer associated with the mutex.
The communication data buffer is a std::string which is stored in the globally addressable tuple. The data buffer contains serialized data structures that are 'shipped' across the network with a remotely invoked active message that fills the buffer and flips the mutex.
Data types should be compatible with Boost or STE||AR HPX Serialization requirements.
Users can select which PE is the 'root' process for communication ('root'
process for the tree communication does not have to be rank 0).
To use the library, create a 'communicator pattern' on each PE, set the root level rank for communication when you create the 'communicator pattern', and you should be all set.
To install, recursively copy the ./include/upcxx_collectives into your
project or your system installation path, usually this is some place like
../include/.
To compile, read the examples directory for guidance. Switching between serializers is as simple as uncommenting the HPX block and commenting the BOOST block in the makefile.
- All2All
- hypercube
Christopher Taylor