/*************************************************************************
 * Copyright (c) 2016-2022, NVIDIA CORPORATION. All rights reserved.
 *
 * See LICENSE.txt for license information
 ************************************************************************/

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

#define ALIGN 4

void HyperCubeGetCollByteCount(size_t *sendcount, size_t *recvcount, size_t *paramcount, size_t *sendInplaceOffset, size_t *recvInplaceOffset, size_t count, size_t eltSize, int nranks) {
  size_t base = (count/nranks) & ~(16/eltSize - 1);
  *sendcount = base;
  *recvcount = base*nranks;
  *sendInplaceOffset = base;
  *recvInplaceOffset = 0;
  *paramcount = base;
}

testResult_t HyperCubeInitData(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, 0, type, ncclSum, 33*rep + rank, 1, 0));
    for (int j=0; j<nranks; j++) {
      TESTCHECK(InitData((char*)args->expected[i] + args->sendBytes*j, sendcount, 0, type, ncclSum, 33*rep + j, 1, 0));
    }
    CUDACHECK(cudaDeviceSynchronize());
  }
  return testSuccess;
}

void HyperCubeGetBw(size_t count, size_t typesize, double sec, double* algBw, double* busBw, int nranks) {
  double baseBw = (double)(count * typesize * (nranks - 1)) / 1.0E9 / sec;

  *algBw = baseBw;
  double factor = 1;
  *busBw = baseBw * factor;
}

testResult_t HyperCubeRunColl(void* sendbuff, size_t sendoffset, void* recvbuff, size_t recvoffset, size_t count, ncclDataType_t type, ncclRedOp_t op, int root, ncclComm_t comm, cudaStream_t stream, int deviceImpl) {
  if (deviceImpl == 0) {
    char* sbuff = ((char*)sendbuff) + sendoffset;
    char* rbuff = ((char*)recvbuff) + recvoffset;
    int nRanks;
    NCCLCHECK(ncclCommCount(comm, &nRanks));
    int rank;
    NCCLCHECK(ncclCommUserRank(comm, &rank));
    size_t rankSize = count * wordSize(type);

    if (rbuff+rank*rankSize != sbuff) CUDACHECK(cudaMemcpyAsync(rbuff+rank*rankSize, sbuff, rankSize, cudaMemcpyDeviceToDevice, stream));

    // Hypercube AllGather
    for (int mask=1; mask<nRanks; mask<<=1) {
      NCCLCHECK(ncclGroupStart());
      int s = rank & ~(mask-1);
      int r = s ^ mask;
      NCCLCHECK(ncclSend(rbuff+s*rankSize, count*mask, type, rank^mask, comm, stream));
      NCCLCHECK(ncclRecv(rbuff+r*rankSize, count*mask, type, rank^mask, comm, stream));
      NCCLCHECK(ncclGroupEnd());
    }
  } else {
    return testNotImplemented;
  }
  return testSuccess;
}

struct testColl hyperCubeTest = {
  "HyperCube",
  HyperCubeGetCollByteCount,
  HyperCubeInitData,
  HyperCubeGetBw,
  HyperCubeRunColl
};

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

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

  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;
  }

  // Check if this is a power of 2
  int nRanks = args->nProcs*args->nThreads*args->nGpus;
  if (nRanks && !(nRanks & (nRanks - 1))) {
    for (int i=0; i<type_count; i++) {
      TESTCHECK(TimeTest(args, run_types[i], run_typenames[i], (ncclRedOp_t)0, "", -1));
    }
  } else {
    printf("nRanks %d is not a power of 2, skipping\n", nRanks);
  }

  return testSuccess;
}

NCCL_WEAK struct testEngine ncclTestEngine = {
  /* .getBuffSize = */ HyperCubeGetBuffSize,
  /* .runTest = */ HyperCubeRunTest
};