/*************************************************************************
 * Copyright (c) 2016-2022, NVIDIA CORPORATION. All rights reserved.
 * Modifications Copyright (c) 2019-2022 Advanced Micro Devices, Inc. All rights reserved.
 *
 * See LICENSE.txt for license information
 ************************************************************************/

#include "common.h"
#include "cuda_runtime.h"

void
GatherGetCollByteCount(size_t* sendcount, size_t* recvcount, size_t* paramcount,
                       size_t* sendInplaceOffset, size_t* recvInplaceOffset, size_t count,
                       size_t eltSize, int nranks)
{
    *sendcount         = (count / nranks) & -(16 / eltSize);
    *recvcount         = (*sendcount) * nranks;
    *sendInplaceOffset = *sendcount;
    *recvInplaceOffset = 0;
    *paramcount        = *sendcount;
}

testResult_t
GatherInitData(struct threadArgs* args, ncclDataType_t type, ncclRedOp_t op, int root,
               int rep, int in_place)
{
    size_t sendcount = args->sendBytes / wordSize(type);
    size_t recvcount = args->expectedBytes / wordSize(type);
    int    nranks    = args->nProcs * args->nThreads * args->nGpus;

    for(int i = 0; i < args->nGpus; i++)
    {
        CUDACHECK(cudaSetDevice(args->gpus[i]));
        int rank = ((args->proc * args->nThreads + args->thread) * args->nGpus + i);
        CUDACHECK(cudaMemset(args->recvbuffs[i], 0, args->expectedBytes));
        void* data = in_place ? ((char*) args->recvbuffs[i]) + rank * args->sendBytes
                              : args->sendbuffs[i];
        TESTCHECK(InitData(data, sendcount, rank * sendcount, type, ncclSum, rep, 1, 0));
        CUDACHECK(cudaMemcpy(args->expected[i], args->recvbuffs[i], args->expectedBytes,
                             cudaMemcpyDefault));
        if(rank == root)
        {
            TESTCHECK(InitData(args->expected[i], nranks * sendcount, 0, type, ncclSum,
                               rep, 1, 0));
        }
        CUDACHECK(cudaDeviceSynchronize());
    }
    return testSuccess;
}

void
GatherGetBw(size_t count, int typesize, double sec, double* algBw, double* busBw,
            int nranks)
{
    double baseBw = (double) (count * nranks * typesize) / 1.0E9 / sec;

    *algBw        = baseBw;
    double factor = ((double) (nranks - 1)) / ((double) (nranks));
    *busBw        = baseBw * factor;
}

testResult_t
GatherRunColl(void* sendbuff, void* recvbuff, size_t count, ncclDataType_t type,
              ncclRedOp_t op, int root, ncclComm_t comm, cudaStream_t stream)
{
    int nRanks;
    NCCLCHECK(ncclCommCount(comm, &nRanks));
    int rank;
    NCCLCHECK(ncclCommUserRank(comm, &rank));
    size_t rankOffset = count * wordSize(type);
    if(count == 0) return testSuccess;

    NCCLCHECK(ncclGroupStart());
    NCCLCHECK(ncclSend(sendbuff, count, type, root, comm, stream));
    if(rank == root)
    {
        for(int r = 0; r < nRanks; r++)
        {
            NCCLCHECK(ncclRecv(((char*) recvbuff) + r * rankOffset, count, type, r, comm,
                               stream));
        }
    }
    NCCLCHECK(ncclGroupEnd());

    return testSuccess;
}

struct testColl gatherTest = { "Gather", GatherGetCollByteCount, GatherInitData,
                               GatherGetBw, GatherRunColl };

void
GatherGetBuffSize(size_t* sendcount, size_t* recvcount, size_t count, int nranks)
{
    size_t paramcount, sendInplaceOffset, recvInplaceOffset;
    GatherGetCollByteCount(sendcount, recvcount, &paramcount, &sendInplaceOffset,
                           &recvInplaceOffset, count, /*eltSize=*/1, nranks);
}

testResult_t
GatherRunTest(struct threadArgs* args, int root, ncclDataType_t type,
              const char* typeName, ncclRedOp_t op, const char* opName)
{
    args->collTest = &gatherTest;
    ncclDataType_t* run_types;
    const char**    run_typenames;
    int             type_count;
    int             begin_root, end_root;

    if((int) type != -1)
    {
        type_count    = 1;
        run_types     = &type;
        run_typenames = &typeName;
    }
    else
    {
        type_count    = test_typenum;
        run_types     = test_types;
        run_typenames = test_typenames;
    }

    if(root != -1)
    {
        begin_root = end_root = root;
    }
    else
    {
        begin_root = 0;
        end_root   = args->nProcs * args->nThreads * args->nGpus - 1;
    }

    for(int i = 0; i < type_count; i++)
    {
        for(int j = begin_root; j <= end_root; j++)
        {
            TESTCHECK(TimeTest(args, run_types[i], run_typenames[i], (ncclRedOp_t) 0,
                               "none", j));
        }
    }
    return testSuccess;
}

struct testEngine ncclTestEngine = { GatherGetBuffSize, GatherRunTest };