AllToAll.hpp

/*
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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
  };
  char a2aModeStr[3][20] = {"Copy", "Read-Only", "Write-Only"};

  // 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 a2aMode       = EnvVars::GetEnvVar("A2A_MODE"       , 0);
  int numGpus       = EnvVars::GetEnvVar("NUM_GPU_DEVICES", numDetectedGpus);
  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);

  // 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      , a2aModeStr[a2aMode]);
    ev.Print("NUM_GPU_DEVICES", numGpus      , "Using %d GPUs", numGpus);
    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 (a2aMode < 0 || a2aMode > 2) {
    printf("[ERROR] a2aMode must be between 0 and 2\n");
    exit(1);
  }
  if (numGpus < 0 || numGpus > numDetectedGpus) {
    printf("[ERROR] Cannot use %d GPUs.  Detected %d GPUs\n", numGpus, numDetectedGpus);
    exit(1);
  }

  // Collect the number of GPU devices to use
  int const numSrcs = (a2aMode == A2A_WRITE_ONLY ? 0 : 1);
  int const numDsts = (a2aMode == A2A_READ_ONLY  ? 0 : 1);

  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;
      if (numSrcs) transfer.srcs.push_back({memType, i});
      if (numDsts) transfer.dsts.push_back({memType, j});
      transfer.exeDevice = {exeType, (useRemoteRead ? j : i)};
      transfer.exeSubIndex = -1;
      transfer.numSubExecs = numSubExecs;

      reIndex[std::make_pair(i,j)] = 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);
  printf("   %cSTotal     %cActual\n", separator, separator);

  double totalBandwidthGpu = 0.0;
  double minExecutorBandwidth = std::numeric_limits<double>::max();
  double maxExecutorBandwidth = 0.0;
  std::vector<double> colTotalBandwidth(numGpus+1, 0.0);
  for (int src = 0; src < numGpus; src++) {
    double rowTotalBandwidth = 0;
    double executorBandwidth = 0;
    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;
        executorBandwidth        = std::max(executorBandwidth,
                                            results.exeResults[transfers[transferIdx].exeDevice].avgBandwidthGbPerSec);
        printf("%c%8.3f  ", separator, r.avgBandwidthGbPerSec);
      } else {
        printf("%c%8s  ", separator, "N/A");
      }
    }
    printf("   %c%8.3f   %c%8.3f\n", separator, rowTotalBandwidth, separator, executorBandwidth);
    minExecutorBandwidth = std::min(minExecutorBandwidth, executorBandwidth);
    maxExecutorBandwidth = std::max(maxExecutorBandwidth, executorBandwidth);
    colTotalBandwidth[numGpus] += rowTotalBandwidth;
  }
  printf("\nRTotal");
  for (int dst = 0; dst < numGpus; dst++) {
    printf("%c%8.3f  ", separator, colTotalBandwidth[dst]);
  }
  printf("   %c%8.3f   %c%8.3f   %c%8.3f\n", separator, colTotalBandwidth[numGpus],
         separator, minExecutorBandwidth, separator, maxExecutorBandwidth);
  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);
}