About

FlagCX is a scalable and adaptive cross-chip communication library developed with the backing of the Beijing Academy of Artificial Intelligence (BAAI).

FlagCX is also a part of FlagAI-Open, an open-source initiative by BAAI that aims to foster an open-source ecosystem for AI technologies. It serves as a platform where developers, researchers, and AI enthusiasts can collaborate on various AI projects, contribute to the development of cutting-edge AI solutions, and share their work with the global community.

FlagCX leverages native collective communication libraries to provide the full support of single-chip communication on different platforms. All supported communication backends are listed as follows:

• NCCL, NVIDIA Collective Communications Library.
• IXCCL, Iluvatar Corex Collective Communications Library.
• CNCL, Cambricon Communications Library.

Quick Start

Build

1. Clone the repository:

   git clone https://github.com/FlagOpen/FlagCX.git

2. Build the library with different flags targeting to different platforms:

   cd FlagCX
   make [USE_NVIDIA/USE_ILUVATAR_COREX/USE_CAMBRICON]=1

   The default install path is set to build/, you can manually set BUILDDIR to specify the build path. You may also define DEVICE_HOME and CCL_HOME to indicate the install paths of device runtime and communication libraries.

Tests

Tests for FlagCX are maintained in test/perf.

cd test/perf
make
./test_allreduce -b 128M -e 8G -f 2

Note that the default MPI install path is set to /usr/local/mpi, you may specify the MPI path with:

make MPI_HOME=<path to mpi install>

All tests support the same set of arguments:

• Sizes to scan
  • -b <min size in bytes> minimum size to start with. Default: 1M.
  • -e <max size in bytes> maximum size to end at. Default: 1G.
  • -f <increment factor> multiplication factor between sizes. Default: 2.
• Performance
  • -w, <warmup iteration count> number of warmup iterations (not timed). Default: 5.
  • -n, <iteration count> number of iterations. Default: 20.
• Utils
  • -p, <0/1> print buffer info. Default: 0.
  • -h print help message. Default: disabled.

License

This project is licensed under the Apache License (Version 2.0).