AllToAll.hpp

/*
Copyright (c) 2024 Advanced Micro Devices, Inc. All rights reserved.

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*/

#include "EnvVars.hpp"

void AllToAllPreset(EnvVars&           ev,
                    size_t      const  numBytesPerTransfer,
                    std::string const  presetName)
{
  enum
  {
    A2A_COPY       = 0,
    A2A_READ_ONLY  = 1,
    A2A_WRITE_ONLY = 2,
    A2A_CUSTOM     = 3,
  };
  char a2aModeStr[4][20] = {"Copy", "Read-Only", "Write-Only", "Custom"};

  // Force single-stream mode for all-to-all benchmark
  ev.useSingleStream = 1;

  // Force to gfx unroll 2 unless explicitly set
  ev.gfxUnroll      = EnvVars::GetEnvVar("GFX_UNROLL", 2);

  int numDetectedGpus = TransferBench::GetNumExecutors(EXE_GPU_GFX);

  // Collect env vars for this preset
  int a2aDirect     = EnvVars::GetEnvVar("A2A_DIRECT"     , 1);
  int a2aLocal      = EnvVars::GetEnvVar("A2A_LOCAL"      , 0);
  int numGpus       = EnvVars::GetEnvVar("NUM_GPU_DEVICES", numDetectedGpus);
  int numQueuePairs = EnvVars::GetEnvVar("NUM_QUEUE_PAIRS", 0);
  int numSubExecs   = EnvVars::GetEnvVar("NUM_SUB_EXEC"   , 8);
  int useDmaExec    = EnvVars::GetEnvVar("USE_DMA_EXEC"   , 0);
  int useFineGrain  = EnvVars::GetEnvVar("USE_FINE_GRAIN" , 1);
  int useRemoteRead = EnvVars::GetEnvVar("USE_REMOTE_READ", 0);

  // A2A_MODE may be 0,1,2 or else custom numSrcs:numDsts
  int numSrcs, numDsts;
  int a2aMode = 0;
  if (getenv("A2A_MODE") && sscanf(getenv("A2A_MODE"), "%d:%d", &numSrcs, &numDsts) == 2) {
    a2aMode = A2A_CUSTOM;
  } else {
    a2aMode = EnvVars::GetEnvVar("A2A_MODE", 0);
    if (a2aMode < 0 || a2aMode > 2) {
      printf("[ERROR] a2aMode must be between 0 and 2, or else numSrcs:numDsts\n");
      exit(1);
    }
    numSrcs = (a2aMode == A2A_WRITE_ONLY ? 0 : 1);
    numDsts = (a2aMode == A2A_READ_ONLY  ? 0 : 1);
  }

  // Print off environment variables
  ev.DisplayEnvVars();
  if (!ev.hideEnv) {
    if (!ev.outputToCsv) printf("[AllToAll Related]\n");
    ev.Print("A2A_DIRECT"     , a2aDirect    , a2aDirect ? "Only using direct links" : "Full all-to-all");
    ev.Print("A2A_LOCAL"      , a2aLocal     , "%s local transfers", a2aLocal ? "Include" : "Exclude");
    ev.Print("A2A_MODE"       , (a2aMode == A2A_CUSTOM) ?  std::to_string(numSrcs) + ":" + std::to_string(numDsts) : std::to_string(a2aMode),
                                (a2aMode == A2A_CUSTOM) ? (std::to_string(numSrcs) + " read(s) " +
                                                           std::to_string(numDsts) + " write(s)").c_str(): a2aModeStr[a2aMode]);
    ev.Print("NUM_GPU_DEVICES", numGpus      , "Using %d GPUs", numGpus);
    ev.Print("NUM_QUEUE_PAIRS", numQueuePairs, "Using %d queue pairs for NIC transfers", numQueuePairs);
    ev.Print("NUM_SUB_EXEC"   , numSubExecs  , "Using %d subexecutors/CUs per Transfer", numSubExecs);
    ev.Print("USE_DMA_EXEC"   , useDmaExec   , "Using %s executor", useDmaExec ? "DMA" : "GFX");
    ev.Print("USE_FINE_GRAIN" , useFineGrain , "Using %s-grained memory", useFineGrain ? "fine" : "coarse");
    ev.Print("USE_REMOTE_READ", useRemoteRead, "Using %s as executor", useRemoteRead ? "DST" : "SRC");
    printf("\n");
  }

  // Validate env vars
  if (numGpus < 0 || numGpus > numDetectedGpus) {
    printf("[ERROR] Cannot use %d GPUs.  Detected %d GPUs\n", numGpus, numDetectedGpus);
    exit(1);
  }
  if (useDmaExec && (numSrcs != 1 || numDsts != 1)) {
    printf("[ERROR] DMA execution can only be used for copies (A2A_MODE=0)\n");
    exit(1);
  }

  // Collect the number of GPU devices to use
  MemType memType = useFineGrain ? MEM_GPU_FINE : MEM_GPU;
  ExeType exeType = useDmaExec ? EXE_GPU_DMA : EXE_GPU_GFX;

  std::map<std::pair<int, int>, int> reIndex;
  std::vector<Transfer> transfers;
  for (int i = 0; i < numGpus; i++) {
    for (int j = 0; j < numGpus; j++) {

      // Check whether or not to execute this pair
      if (i == j) {
        if (!a2aLocal) continue;
      } else if (a2aDirect) {
#if !defined(__NVCC__)
        uint32_t linkType, hopCount;
        HIP_CALL(hipExtGetLinkTypeAndHopCount(i, j, &linkType, &hopCount));
        if (hopCount != 1) continue;
#endif
      }

      // Build Transfer and add it to list
      TransferBench::Transfer transfer;
      transfer.numBytes = numBytesPerTransfer;
      for (int x = 0; x < numSrcs; x++) transfer.srcs.push_back({memType, i});

      // When using multiple destinations, the additional destinations are "local"
      if (numDsts) transfer.dsts.push_back({memType, j});
      for (int x = 1; x < numDsts; x++) transfer.dsts.push_back({memType, i});
      transfer.exeDevice = {exeType, (useRemoteRead ? j : i)};
      transfer.exeSubIndex = -1;
      transfer.numSubExecs = numSubExecs;

      reIndex[std::make_pair(i,j)] = transfers.size();
      transfers.push_back(transfer);
    }
  }

  // Create a ring using NICs
  std::vector<int> nicTransferIdx(numGpus);
  if (numQueuePairs > 0) {
    int numNics = TransferBench::GetNumExecutors(EXE_NIC);
    for (int i = 0; i < numGpus; i++) {
      TransferBench::Transfer transfer;
      transfer.numBytes = numBytesPerTransfer;
      transfer.srcs.push_back({memType, i});
      transfer.dsts.push_back({memType, (i+1) % numGpus});
      transfer.exeDevice = {TransferBench::EXE_NIC_NEAREST, i};
      transfer.exeSubIndex = (i+1) % numGpus;
      transfer.numSubExecs = numQueuePairs;
      nicTransferIdx[i] = transfers.size();
      transfers.push_back(transfer);
    }
  }

  printf("GPU-GFX All-To-All benchmark:\n");
  printf("==========================\n");
  printf("- Copying %lu bytes between %s pairs of GPUs using %d CUs (%lu Transfers)\n",
         numBytesPerTransfer, a2aDirect ? "directly connected" : "all", numSubExecs, transfers.size());
  if (transfers.size() == 0) return;

  // Execute Transfers
  TransferBench::ConfigOptions cfg = ev.ToConfigOptions();
  TransferBench::TestResults results;
  if (!TransferBench::RunTransfers(cfg, transfers, results)) {
    for (auto const& err : results.errResults)
      printf("%s\n", err.errMsg.c_str());
    exit(0);
  } else {
    PrintResults(ev, 1, transfers, results);
  }

  // Print results
  char separator = (ev.outputToCsv ? ',' : ' ');
  printf("\nSummary: [%lu bytes per Transfer]\n", numBytesPerTransfer);
  printf("==========================================================\n");
  printf("SRC\\DST ");
  for (int dst = 0; dst < numGpus; dst++)
    printf("%cGPU %02d    ", separator, dst);
  if (numQueuePairs > 0)
    printf("%cNIC(%02d QP)", separator, numQueuePairs);
  printf("   %cSTotal     %cActual\n", separator, separator);

  double totalBandwidthGpu = 0.0;
  double minActualBandwidth = std::numeric_limits<double>::max();
  double maxActualBandwidth = 0.0;
  std::vector<double> colTotalBandwidth(numGpus+2, 0.0);
  for (int src = 0; src < numGpus; src++) {
    double rowTotalBandwidth = 0;
    int    transferCount = 0;
    double minBandwidth = std::numeric_limits<double>::max();
    printf("GPU %02d", src);
    for (int dst = 0; dst < numGpus; dst++) {
      if (reIndex.count(std::make_pair(src, dst))) {
        int const transferIdx = reIndex[std::make_pair(src,dst)];
        TransferBench::TransferResult const& r = results.tfrResults[transferIdx];
        colTotalBandwidth[dst]  += r.avgBandwidthGbPerSec;
        rowTotalBandwidth       += r.avgBandwidthGbPerSec;
        totalBandwidthGpu       += r.avgBandwidthGbPerSec;
        minBandwidth             = std::min(minBandwidth, r.avgBandwidthGbPerSec);
        transferCount++;
        printf("%c%8.3f  ", separator, r.avgBandwidthGbPerSec);
      } else {
        printf("%c%8s  ", separator, "N/A");
      }
    }

    if (numQueuePairs > 0) {
      TransferBench::TransferResult const& r = results.tfrResults[nicTransferIdx[src]];
      colTotalBandwidth[numGpus]  += r.avgBandwidthGbPerSec;
      rowTotalBandwidth           += r.avgBandwidthGbPerSec;
      totalBandwidthGpu           += r.avgBandwidthGbPerSec;
      minBandwidth                 = std::min(minBandwidth, r.avgBandwidthGbPerSec);
      transferCount++;
      printf("%c%8.3f  ", separator, r.avgBandwidthGbPerSec);
    }
    double actualBandwidth = minBandwidth * transferCount;
    printf("   %c%8.3f   %c%8.3f\n", separator, rowTotalBandwidth, separator, actualBandwidth);
    minActualBandwidth = std::min(minActualBandwidth, actualBandwidth);
    maxActualBandwidth = std::max(maxActualBandwidth, actualBandwidth);
    colTotalBandwidth[numGpus+1] += rowTotalBandwidth;
  }
  printf("\nRTotal");
  for (int dst = 0; dst < numGpus; dst++) {
    printf("%c%8.3f  ", separator, colTotalBandwidth[dst]);
  }
  if (numQueuePairs > 0) {
    printf("%c%8.3f  ", separator, colTotalBandwidth[numGpus]);
  }
  printf("   %c%8.3f   %c%8.3f   %c%8.3f\n", separator, colTotalBandwidth[numGpus+1],
         separator, minActualBandwidth, separator, maxActualBandwidth);
  printf("\n");

  printf("Average   bandwidth (GPU Timed): %8.3f GB/s\n", totalBandwidthGpu / transfers.size());
  printf("Aggregate bandwidth (GPU Timed): %8.3f GB/s\n", totalBandwidthGpu);
  printf("Aggregate bandwidth (CPU Timed): %8.3f GB/s\n", results.avgTotalBandwidthGbPerSec);

  PrintErrors(results.errResults);
}