Unified Communication X Files

1.19.0 (August 6, 2025)

Features:

UCP

• Enabled multi-GPU support within a single process
• Added dynamic selection between strong and weak fences in RMA flush operations
• Improved endpoint reconfiguration capabilities
• Added All2All lane selection for multi-NIC-GPU systems
• Improved rkey debug info when config cache limit is reached
• Improved UCP protocol selection based on available memory types
• Removed dummy memory key from irrelevant transports (TCP, CMA and CUDA)
• Improved RNDV performance with device-local staging buffers
• Enabled error handling for RMA get_offload protocols

UCT

• Defined uct_rkey_unpack_v2 API to support passing sys-dev

RDMA CORE (IB, ROCE, etc.)

• Added SRD transport support in EFA with reordering, AM, and control operations
• Removed XGVMI BF2 support (umem)
• Removed device memory indirect key
• Fixed VFS objects for DCIs and pools
• Added routing table cache to the reachability check
• Fixed strict order usage in IB auxiliary rkeys
• Improved various init logging messages

CUDA

• Added multi-context support for remote key unpacking to CUDA IPC
• Added context switching aware resource management to CUDA IPC
• Use buffer ID to detect VA recycling in CUDA IPC
• Added support for allocating CUDA memory on specific system devices
• Added multi-device support in CUDA copy
• Improved protocol lane selection for GPU memory operations
• Relaxed CUDA context requirements in CUDA copy
• Added deadlock prevention in CUDA copy
• Added support for address range detection for VMM
• Enabled memory attributes query after switching CUDA GPU
• Added multi-GPU send tests for CUDA transports
• Removed host-to-host performance estimation from CUDA copy transport
• Replaced cuCtxCreate by cuDevicePrimaryCtxRetain
• Improved various init logging messages

ROCM

• Added control parameters for IPC handle cache and signal pool size
• Optimized ROCm memory type detection with caching

UCS

• Removed compilation warnings

Tools

• Added name filter option (-F 'str') to ucx_info for config and feature dumps
• Improved ucx_info input validation

Bugfixes:

UCP

• Made UCX_TLS=^ib disable all transports including auxiliary
• Fixed send request status handling
• Fixed performance degradation in RNDV by optimizing md cache updates
• Fixed protocol selection when first lane is filtered out by fragment size
• Fixed rkey selection by using memory registration flag

UCT

RDMA CORE (IB, ROCE, etc.)

• Improved reliability of DC transport by adding DCI validation and separating connection logic
• Fixed segfault in DC fence operation

GPU (CUDA, ROCM)

• Updated ROCm configuration for ROCm 6.3 compatibility
• Fixed system device detection for CUDA async memory operations
• Fixed legacy type detection during CUDA IPC mpack
• Fixed CUDA IPC RMA operations by using correct context for local buffers

UCS

• Use UCS function for counting leading zeros on x86 architecture
• Fixed a compilation warning

Shared Memory

• Fixed FIFO availability check for sm transport

Documentation

• Fixed open-mpi clone instruction

Build

• Fixed enum-int-mismatch warnings with GCC 15