Issues

• TL/UCP: reduce_scatter defaults to ring, knomial is up to 16x faster on a single node

  openucx/ucc#1357 · Filter by author bwestheimer opened on Sep 15, 2026

• TEST/MPI: persistent alltoallv with 32-bit counts hangs after validation overwrites scounts

  openucx/ucc#1334 · Filter by author wfaderhold21 opened on Jul 29, 2026

• Allreduce ring optimization

  openucx/ucc#1293 · Filter by author janjust opened on Apr 8, 2026
  

• NCCL backend from UCC installed in NVHPCSDK

  openucx/ucc#1249 · Filter by author bellenlau opened on Dec 22, 2025
  3

• Can't force SHARP with score map tuning

  openucx/ucc#1243 · Filter by author james-sungjae-lee opened on Dec 17, 2025
  4

• Why does UCC consistently insist on using software to simulate PUT/GET operations?

  openucx/ucc#1232 · Filter by author TroyMitchell911 opened on Dec 2, 2025
  5

• UTIL: cfg parser respect inherited vars fix

  openucx/ucc#1210 · Filter by author janjust opened on Oct 30, 2025
  

• UCC calling HCOLL in version 1.4.0

  openucx/ucc#1197 · Filter by author bellenlau opened on Oct 15, 2025
  1

• Support for macOS

  openucx/ucc#1182 · Filter by author Jacobfaib opened on Aug 27, 2025
  1

• Graceful Failure with Incorrect API Usage

  openucx/ucc#1174 · Filter by author wfaderhold21 opened on Aug 5, 2025

• AllReduce with SHARP TL not being selected

  openucx/ucc#1164 · Filter by author NiharKod opened on Jul 24, 2025
  8

• Does UCC expose point-to-point communication API?

  openucx/ucc#1139 · Filter by author MaoZiming opened on Jun 4, 2025
  1

• Tests fail with Assertion `ucs_async_check_owner_thread(&(worker)->async)' in the UCC release 1.4.4

  openucx/ucc#1132 · Filter by author lahwaacz opened on May 10, 2025
  3

• test_context.global fails with UCX 1.17.0 and newer

  openucx/ucc#1090 · Filter by author lahwaacz opened on Mar 8, 2025

• could we publish ucc on vcpkg package manager

  openucx/ucc#1086 · Filter by author mullerhai opened on Mar 4, 2025
  7

• Add option to create teams with only specific TLs

  openucx/ucc#1056 · Filter by author almogsegal opened on Dec 11, 2024

• Disable unsupported TLs when CUDA Graph capture is in progress

  openucx/ucc#1055 · Filter by author almogsegal opened on Dec 11, 2024

• raise min UCX version in anticipation of release

  openucx/ucc#1048 · Filter by author janjust opened on Nov 14, 2024
  

• Performance degradation on TL/CUDA/ALLGATHER

  openucx/ucc#1042 · Filter by author samnordmann opened on Oct 28, 2024
  2

• Error and hang on v100

  openucx/ucc#1041 · Filter by author samnordmann opened on Oct 28, 2024
  1

• Question about communication between Nvidia and AMD GPUs

  openucx/ucc#1039 · Filter by author YangZhou1997 opened on Oct 17, 2024
  3

• Question about ucc topology

  openucx/ucc#1034 · Filter by author MC952-arch opened on Oct 12, 2024
  1

• ucc compilation is getting failed on master branch

  openucx/ucc#1031 · Filter by author shashank-parsi opened on Oct 8, 2024
  5

• Some puzzled problems about algorithm

  openucx/ucc#1018 · Filter by author Luckyton opened on Sep 4, 2024
  1

• --with-nvcc-gencode help text differs slightly from expected format

  openucx/ucc#1003 · Filter by author mhrywniak opened on Jul 25, 2024