NCCL API

The following sections describe the NCCL methods and operations.

• Communicator Creation and Management Functions
  • ncclGetLastError
  • ncclGetErrorString
  • ncclGetVersion
  • ncclGetUniqueId
  • ncclCommInitRank
  • ncclCommInitAll
  • ncclCommInitRankConfig
  • ncclCommInitRankScalable
  • ncclCommSplit
  • ncclCommShrink
  • ncclCommGetUniqueId
  • ncclCommGrow
  • ncclCommFinalize
  • ncclCommRevoke
  • ncclCommDestroy
  • ncclCommAbort
  • ncclCommGetAsyncError
  • ncclCommCount
  • ncclCommCuDevice
  • ncclCommUserRank
  • ncclCommRegister
  • ncclCommDeregister
  • ncclCommWindowRegister
  • ncclCommWindowDeregister
  • ncclMemAlloc
  • ncclMemFree
• Collective Communication Functions
  • ncclAllReduce
  • ncclBroadcast
  • ncclReduce
  • ncclAllGather
  • ncclReduceScatter
  • ncclAlltoAll
  • ncclGather
  • ncclScatter
• Group Calls
  • ncclGroupStart
  • ncclGroupEnd
  • ncclGroupSimulateEnd
• Point To Point Communication Functions
  • Two-Sided Point-to-Point Operations
    • ncclSend
    • ncclRecv
  • One-Sided Point-to-Point Operations (RMA)
    • ncclPutSignal
    • ncclSignal
    • ncclWaitSignal
• Types
  • ncclComm_t
  • ncclResult_t
  • ncclDataType_t
  • ncclRedOp_t
  • ncclScalarResidence_t
  • ncclConfig_t
  • ncclSimInfo_t
  • ncclWindow_t
• User Defined Reduction Operators
  • ncclRedOpCreatePreMulSum
  • ncclRedOpDestroy
• NCCL API Supported Flags
  • Window Registration Flags
  • NCCL Communicator CTA Policy Flags
  • Communicator Shrink Flags
• Device API
  • Host-Side Setup
    • ncclDevComm
    • ncclDevCommCreate
    • ncclDevCommDestroy
    • ncclDevCommRequirements
    • ncclCommQueryProperties
    • ncclCommProperties_t
    • ncclGinType_t
  • LSA
    • ncclLsaBarrierSession
    • ncclGetPeerPointer
    • ncclGetLsaPointer
    • ncclGetLocalPointer
  • Multimem
    • ncclGetLsaMultimemPointer
  • Host-Accessible Device Pointer Functions
    • ncclGetLsaMultimemDevicePointer
    • ncclGetMultimemDevicePointer
    • ncclGetLsaDevicePointer
    • ncclGetPeerDevicePointer
  • GIN
    • ncclGin
    • Signals and Counters
    • ncclGinBarrierSession