/*************************************************************************
* Copyright (c) 2015-2021, NVIDIA CORPORATION. All rights reserved.
*
* See LICENSE.txt for license information
************************************************************************/
#ifndef NCCL_H_
#define NCCL_H_
#include <cuda_runtime.h>
#include <cuda_fp16.h>
#if CUDART_VERSION >= 11000
#include <cuda_bf16.h>
#endif
#define NCCL_MAJOR 2
#define NCCL_MINOR 19
#define NCCL_PATCH 3
#define NCCL_SUFFIX ""
#define NCCL_VERSION_CODE 21903
#define NCCL_VERSION(X,Y,Z) (((X) <= 2 && (Y) <= 8) ? (X) * 1000 + (Y) * 100 + (Z) : (X) * 10000 + (Y) * 100 + (Z))
#ifdef __cplusplus
extern "C" {
#endif
#include <limits.h>
/* Opaque handle to communicator */
typedef struct ncclComm* ncclComm_t;
#define NCCL_COMM_NULL NULL
#define NCCL_UNIQUE_ID_BYTES 128
typedef struct { char internal[NCCL_UNIQUE_ID_BYTES]; } ncclUniqueId;
/* Error type */
typedef enum { ncclSuccess = 0,
ncclUnhandledCudaError = 1,
ncclSystemError = 2,
ncclInternalError = 3,
ncclInvalidArgument = 4,
ncclInvalidUsage = 5,
ncclRemoteError = 6,
ncclInProgress = 7,
ncclNumResults = 8 } ncclResult_t;
#define NCCL_CONFIG_UNDEF_INT INT_MIN
#define NCCL_CONFIG_UNDEF_PTR NULL
#define NCCL_SPLIT_NOCOLOR -1
/* Communicator configuration. Users can assign value to attributes to specify the
* behavior of a communicator. */
typedef struct ncclConfig_v21700 {
/* attributes that users should never touch. */
size_t size;
unsigned int magic;
unsigned int version;
/* attributes that users are able to customize. */
int blocking;
int cgaClusterSize;
int minCTAs;
int maxCTAs;
const char *netName;
int splitShare;
} ncclConfig_t;
/* Config initializer must be assigned to initialize config structure when it is created.
* Not initialized config will result in NCCL error. */
#define NCCL_CONFIG_INITIALIZER { \
sizeof(ncclConfig_t), /* size */ \
0xcafebeef, /* magic */ \
NCCL_VERSION(NCCL_MAJOR, NCCL_MINOR, NCCL_PATCH), /* version */ \
NCCL_CONFIG_UNDEF_INT, /* blocking */ \
NCCL_CONFIG_UNDEF_INT, /* cgaClusterSize */ \
NCCL_CONFIG_UNDEF_INT, /* minCTAs */ \
NCCL_CONFIG_UNDEF_INT, /* maxCTAs */ \
NCCL_CONFIG_UNDEF_PTR, /* netName */ \
NCCL_CONFIG_UNDEF_INT /* splitShare */ \
}
/* NCCL malloc and free function for all types of NCCL optimizations
* (e.g. user buffer registration). The actual allocated size might
* be larger than requested due to granularity requirement. */
ncclResult_t ncclMemAlloc(void** ptr, size_t size);
ncclResult_t pncclMemAlloc(void** ptr, size_t size);
ncclResult_t ncclMemFree(void *ptr);
ncclResult_t pncclMemFree(void *ptr);
/* Return the NCCL_VERSION_CODE of the NCCL library in the supplied integer.
* This integer is coded with the MAJOR, MINOR and PATCH level of the
* NCCL library
*/
ncclResult_t ncclGetVersion(int *version);
ncclResult_t pncclGetVersion(int *version);
/* Generates an Id to be used in ncclCommInitRank. ncclGetUniqueId should be
* called once and the Id should be distributed to all ranks in the
* communicator before calling ncclCommInitRank. */
ncclResult_t ncclGetUniqueId(ncclUniqueId* uniqueId);
ncclResult_t pncclGetUniqueId(ncclUniqueId* uniqueId);
/* Create a new communicator (multi thread/process version) with a configuration
* set by users. */
ncclResult_t ncclCommInitRankConfig(ncclComm_t* comm, int nranks, ncclUniqueId commId, int rank, ncclConfig_t* config);
ncclResult_t pncclCommInitRankConfig(ncclComm_t* comm, int nranks, ncclUniqueId commId, int rank, ncclConfig_t* config);
/* Creates a new communicator (multi thread/process version).
* rank must be between 0 and nranks-1 and unique within a communicator clique.
* Each rank is associated to a CUDA device, which has to be set before calling
* ncclCommInitRank.
* ncclCommInitRank implicitly syncronizes with other ranks, so it must be
* called by different threads/processes or use ncclGroupStart/ncclGroupEnd. */
ncclResult_t ncclCommInitRank(ncclComm_t* comm, int nranks, ncclUniqueId commId, int rank);
ncclResult_t pncclCommInitRank(ncclComm_t* comm, int nranks, ncclUniqueId commId, int rank);
/* Creates a clique of communicators (single process version).
* This is a convenience function to create a single-process communicator clique.
* Returns an array of ndev newly initialized communicators in comm.
* comm should be pre-allocated with size at least ndev*sizeof(ncclComm_t).
* If devlist is NULL, the first ndev CUDA devices are used.
* Order of devlist defines user-order of processors within the communicator. */
ncclResult_t ncclCommInitAll(ncclComm_t* comm, int ndev, const int* devlist);
ncclResult_t pncclCommInitAll(ncclComm_t* comm, int ndev, const int* devlist);
/* Finalize a communicator. ncclCommFinalize flushes all issued communications,
* and marks communicator state as ncclInProgress. The state will change to ncclSuccess
* when the communicator is globally quiescent and related resources are freed; then,
* calling ncclCommDestroy can locally free the rest of the resources (e.g. communicator
* itself) without blocking. */
ncclResult_t ncclCommFinalize(ncclComm_t comm);
ncclResult_t pncclCommFinalize(ncclComm_t comm);
/* Frees local resources associated with communicator object. */
ncclResult_t ncclCommDestroy(ncclComm_t comm);
ncclResult_t pncclCommDestroy(ncclComm_t comm);
/* Frees resources associated with communicator object and aborts any operations
* that might still be running on the device. */
ncclResult_t ncclCommAbort(ncclComm_t comm);
ncclResult_t pncclCommAbort(ncclComm_t comm);
/* Creates one or more communicators from an existing one.
* Ranks with the same color will end up in the same communicator.
* Within the new communicator, key will be used to order ranks.
* NCCL_SPLIT_NOCOLOR as color will indicate the rank will not be part of any group
* and will therefore return a NULL communicator.
* If config is NULL, the new communicator will inherit the original communicator's
* configuration*/
ncclResult_t ncclCommSplit(ncclComm_t comm, int color, int key, ncclComm_t *newcomm, ncclConfig_t* config);
ncclResult_t pncclCommSplit(ncclComm_t comm, int color, int key, ncclComm_t *newcomm, ncclConfig_t* config);
/* Returns a string for each error code. */
const char* ncclGetErrorString(ncclResult_t result);
const char* pncclGetErrorString(ncclResult_t result);
/* Returns a human-readable message of the last error that occurred.
* comm is currently unused and can be set to NULL
*/
const char* ncclGetLastError(ncclComm_t comm);
const char* pncclGetLastError(ncclComm_t comm);
/* Checks whether the comm has encountered any asynchronous errors */
ncclResult_t ncclCommGetAsyncError(ncclComm_t comm, ncclResult_t *asyncError);
ncclResult_t pncclCommGetAsyncError(ncclComm_t comm, ncclResult_t *asyncError);
/* Gets the number of ranks in the communicator clique. */
ncclResult_t ncclCommCount(const ncclComm_t comm, int* count);
ncclResult_t pncclCommCount(const ncclComm_t comm, int* count);
/* Returns the cuda device number associated with the communicator. */
ncclResult_t ncclCommCuDevice(const ncclComm_t comm, int* device);
ncclResult_t pncclCommCuDevice(const ncclComm_t comm, int* device);
/* Returns the user-ordered "rank" associated with the communicator. */
ncclResult_t ncclCommUserRank(const ncclComm_t comm, int* rank);
ncclResult_t pncclCommUserRank(const ncclComm_t comm, int* rank);
/* Reduction operation selector */
typedef enum { ncclNumOps_dummy = 5 } ncclRedOp_dummy_t;
typedef enum { ncclSum = 0,
ncclProd = 1,
ncclMax = 2,
ncclMin = 3,
ncclAvg = 4,
/* ncclNumOps: The number of built-in ncclRedOp_t values. Also
* serves as the least possible value for dynamic ncclRedOp_t's
* as constructed by ncclRedOpCreate*** functions. */
ncclNumOps = 5,
/* ncclMaxRedOp: The largest valid value for ncclRedOp_t.
* It is defined to be the largest signed value (since compilers
* are permitted to use signed enums) that won't grow
* sizeof(ncclRedOp_t) when compared to previous NCCL versions to
* maintain ABI compatibility. */
ncclMaxRedOp = 0x7fffffff>>(32-8*sizeof(ncclRedOp_dummy_t))
} ncclRedOp_t;
/* Data types */
typedef enum { ncclInt8 = 0, ncclChar = 0,
ncclUint8 = 1,
ncclInt32 = 2, ncclInt = 2,
ncclUint32 = 3,
ncclInt64 = 4,
ncclUint64 = 5,
ncclFloat16 = 6, ncclHalf = 6,
ncclFloat32 = 7, ncclFloat = 7,
ncclFloat64 = 8, ncclDouble = 8,
#if defined(__CUDA_BF16_TYPES_EXIST__)
ncclBfloat16 = 9,
ncclNumTypes = 10
#else
ncclNumTypes = 9
#endif
} ncclDataType_t;
/* ncclScalarResidence_t: Location and dereferencing logic for scalar arguments. */
typedef enum {
/* ncclScalarDevice: The scalar is in device-visible memory and will be
* dereferenced while the collective is running. */
ncclScalarDevice = 0,
/* ncclScalarHostImmediate: The scalar is in host-visible memory and will be
* dereferenced before the ncclRedOpCreate***() function returns. */
ncclScalarHostImmediate = 1
} ncclScalarResidence_t;
/*
* ncclRedOpCreatePreMulSum
*
* Creates a new reduction operator which pre-multiplies input values by a given
* scalar locally before reducing them with peer values via summation. For use
* only with collectives launched against *comm* and *datatype*. The
* *residence* argument indicates how/when the memory pointed to by *scalar*
* will be dereferenced. Upon return, the newly created operator's handle
* is stored in *op*.
*/
ncclResult_t ncclRedOpCreatePreMulSum(ncclRedOp_t *op, void *scalar, ncclDataType_t datatype, ncclScalarResidence_t residence, ncclComm_t comm);
ncclResult_t pncclRedOpCreatePreMulSum(ncclRedOp_t *op, void *scalar, ncclDataType_t datatype, ncclScalarResidence_t residence, ncclComm_t comm);
/*
* ncclRedOpDestroy
*
* Destroys the reduction operator *op*. The operator must have been created by
* ncclRedOpCreatePreMul with the matching communicator *comm*. An operator may be
* destroyed as soon as the last NCCL function which is given that operator returns.
*/
ncclResult_t ncclRedOpDestroy(ncclRedOp_t op, ncclComm_t comm);
ncclResult_t pncclRedOpDestroy(ncclRedOp_t op, ncclComm_t comm);
/*
* Collective communication operations
*
* Collective communication operations must be called separately for each
* communicator in a communicator clique.
*
* They return when operations have been enqueued on the CUDA stream.
*
* Since they may perform inter-CPU synchronization, each call has to be done
* from a different thread or process, or need to use Group Semantics (see
* below).
*/
/*
* Reduce
*
* Reduces data arrays of length count in sendbuff into recvbuff using op
* operation.
* recvbuff may be NULL on all calls except for root device.
* root is the rank (not the CUDA device) where data will reside after the
* operation is complete.
*
* In-place operation will happen if sendbuff == recvbuff.
*/
ncclResult_t ncclReduce(const void* sendbuff, void* recvbuff, size_t count, ncclDataType_t datatype,
ncclRedOp_t op, int root, ncclComm_t comm, cudaStream_t stream);
ncclResult_t pncclReduce(const void* sendbuff, void* recvbuff, size_t count, ncclDataType_t datatype,
ncclRedOp_t op, int root, ncclComm_t comm, cudaStream_t stream);
/*
* (deprecated) Broadcast (in-place)
*
* Copies count values from root to all other devices.
* root is the rank (not the CUDA device) where data resides before the
* operation is started.
*
* This operation is implicitely in place.
*/
ncclResult_t ncclBcast(void* buff, size_t count, ncclDataType_t datatype, int root,
ncclComm_t comm, cudaStream_t stream);
ncclResult_t pncclBcast(void* buff, size_t count, ncclDataType_t datatype, int root,
ncclComm_t comm, cudaStream_t stream);
/*
* Broadcast
*
* Copies count values from root to all other devices.
* root is the rank (not the CUDA device) where data resides before the
* operation is started.
*
* In-place operation will happen if sendbuff == recvbuff.
*/
ncclResult_t ncclBroadcast(const void* sendbuff, void* recvbuff, size_t count, ncclDataType_t datatype, int root,
ncclComm_t comm, cudaStream_t stream);
ncclResult_t pncclBroadcast(const void* sendbuff, void* recvbuff, size_t count, ncclDataType_t datatype, int root,
ncclComm_t comm, cudaStream_t stream);
/*
* All-Reduce
*
* Reduces data arrays of length count in sendbuff using op operation, and
* leaves identical copies of result on each recvbuff.
*
* In-place operation will happen if sendbuff == recvbuff.
*/
ncclResult_t ncclAllReduce(const void* sendbuff, void* recvbuff, size_t count,
ncclDataType_t datatype, ncclRedOp_t op, ncclComm_t comm, cudaStream_t stream);
ncclResult_t pncclAllReduce(const void* sendbuff, void* recvbuff, size_t count,
ncclDataType_t datatype, ncclRedOp_t op, ncclComm_t comm, cudaStream_t stream);
/*
* Reduce-Scatter
*
* Reduces data in sendbuff using op operation and leaves reduced result
* scattered over the devices so that recvbuff on rank i will contain the i-th
* block of the result.
* Assumes sendcount is equal to nranks*recvcount, which means that sendbuff
* should have a size of at least nranks*recvcount elements.
*
* In-place operations will happen if recvbuff == sendbuff + rank * recvcount.
*/
ncclResult_t ncclReduceScatter(const void* sendbuff, void* recvbuff,
size_t recvcount, ncclDataType_t datatype, ncclRedOp_t op, ncclComm_t comm,
cudaStream_t stream);
ncclResult_t pncclReduceScatter(const void* sendbuff, void* recvbuff,
size_t recvcount, ncclDataType_t datatype, ncclRedOp_t op, ncclComm_t comm,
cudaStream_t stream);
/*
* All-Gather
*
* Each device gathers sendcount values from other GPUs into recvbuff,
* receiving data from rank i at offset i*sendcount.
* Assumes recvcount is equal to nranks*sendcount, which means that recvbuff
* should have a size of at least nranks*sendcount elements.
*
* In-place operations will happen if sendbuff == recvbuff + rank * sendcount.
*/
ncclResult_t ncclAllGather(const void* sendbuff, void* recvbuff, size_t sendcount,
ncclDataType_t datatype, ncclComm_t comm, cudaStream_t stream);
ncclResult_t pncclAllGather(const void* sendbuff, void* recvbuff, size_t sendcount,
ncclDataType_t datatype, ncclComm_t comm, cudaStream_t stream);
/*
* Send
*
* Send data from sendbuff to rank peer.
*
* Rank peer needs to call ncclRecv with the same datatype and the same count from this
* rank.
*
* This operation is blocking for the GPU. If multiple ncclSend and ncclRecv operations
* need to progress concurrently to complete, they must be fused within a ncclGroupStart/
* ncclGroupEnd section.
*/
ncclResult_t ncclSend(const void* sendbuff, size_t count, ncclDataType_t datatype, int peer,
ncclComm_t comm, cudaStream_t stream);
ncclResult_t pncclSend(const void* sendbuff, size_t count, ncclDataType_t datatype, int peer,
ncclComm_t comm, cudaStream_t stream);
/*
* Receive
*
* Receive data from rank peer into recvbuff.
*
* Rank peer needs to call ncclSend with the same datatype and the same count to this
* rank.
*
* This operation is blocking for the GPU. If multiple ncclSend and ncclRecv operations
* need to progress concurrently to complete, they must be fused within a ncclGroupStart/
* ncclGroupEnd section.
*/
ncclResult_t pncclRecv(void* recvbuff, size_t count, ncclDataType_t datatype, int peer,
ncclComm_t comm, cudaStream_t stream);
ncclResult_t ncclRecv(void* recvbuff, size_t count, ncclDataType_t datatype, int peer,
ncclComm_t comm, cudaStream_t stream);
/*
* Group semantics
*
* When managing multiple GPUs from a single thread, and since NCCL collective
* calls may perform inter-CPU synchronization, we need to "group" calls for
* different ranks/devices into a single call.
*
* Grouping NCCL calls as being part of the same collective operation is done
* using ncclGroupStart and ncclGroupEnd. ncclGroupStart will enqueue all
* collective calls until the ncclGroupEnd call, which will wait for all calls
* to be complete. Note that for collective communication, ncclGroupEnd only
* guarantees that the operations are enqueued on the streams, not that
* the operation is effectively done.
*
* Both collective communication and ncclCommInitRank can be used in conjunction
* of ncclGroupStart/ncclGroupEnd, but not together.
*
* Group semantics also allow to fuse multiple operations on the same device
* to improve performance (for aggregated collective calls), or to permit
* concurrent progress of multiple send/receive operations.
*/
/*
* Group Start
*
* Start a group call. All calls to NCCL until ncclGroupEnd will be fused into
* a single NCCL operation. Nothing will be started on the CUDA stream until
* ncclGroupEnd.
*/
ncclResult_t ncclGroupStart();
ncclResult_t pncclGroupStart();
/*
* Group End
*
* End a group call. Start a fused NCCL operation consisting of all calls since
* ncclGroupStart. Operations on the CUDA stream depending on the NCCL operations
* need to be called after ncclGroupEnd.
*/
ncclResult_t ncclGroupEnd();
ncclResult_t pncclGroupEnd();
/* Register CUDA buffer for zero-copy operation */
ncclResult_t ncclCommRegister(const ncclComm_t comm, void* buff, size_t size, void** handle);
ncclResult_t pncclCommRegister(const ncclComm_t comm, void* buff, size_t size, void** handle);
/* Deregister CUDA buffer */
ncclResult_t ncclCommDeregister(const ncclComm_t comm, void* handle);
ncclResult_t pncclCommDeregister(const ncclComm_t comm, void* handle);
#ifdef __cplusplus
} // end extern "C"
#endif
#endif // end include guard