Parameters

Read access to NCCL’s tunable parameters. See Environment Variables for the meaning of each parameter and how to set it.

import nccl.core

nccl.core.params["NCCL_DEBUG"]     # value of a single parameter
list(nccl.core.params)             # every parameter name
nccl.core.dump_params()            # print all parameters to stdout

params

nccl.core.params: Read-only Mapping of NCCL parameter names to their current values, backed by ncclParamGetParameter() and ncclParamGetAllParameterKeys(). Values are returned as strings. Lookups are live: each access queries NCCL rather than a cached snapshot.

dump_params

nccl.core.dump_params() → None: Print NCCL parameters to stdout. Set NCCL_PARAM_DUMP_ALL=1 to include internal parameters.