AllToAllSweep.hpp

/*
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*/

#include "EnvVars.hpp"

void AllToAllSweepPreset(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;

  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 showMinOnly   = EnvVars::GetEnvVar("SHOW_MIN_ONLY",   1);
  int useFineGrain  = EnvVars::GetEnvVar("USE_FINE_GRAIN" , 1);
  int useRemoteRead = EnvVars::GetEnvVar("USE_REMOTE_READ", 0);
  int useSpray      = EnvVars::GetEnvVar("USE_SPRAY",       0);
  int verbose       = EnvVars::GetEnvVar("VERBOSE",         0);

  std::vector<int> blockList  = EnvVars::GetEnvVarArray("BLOCKSIZES", {256});
  std::vector<int> unrollList = EnvVars::GetEnvVarArray("UNROLLS", {1,2,3,4,6,8});
  std::vector<int> numCusList = EnvVars::GetEnvVarArray("NUM_CUS", {4,8,12,16,24,32});

  // 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("BLOCKSIZES"     , blockList.size() , EnvVars::ToStr(blockList).c_str());
    ev.Print("SHOW_MIN_ONLY"  , showMinOnly      , showMinOnly ? "Showing only slowest GPU results" : "Showing slowest and fastest GPU results");
    ev.Print("NUM_CUS"        , numCusList.size(), EnvVars::ToStr(numCusList).c_str());
    ev.Print("NUM_GPU_DEVICES", numGpus          , "Using %d GPUs", numGpus);
    ev.Print("UNROLLS"        , unrollList.size(), EnvVars::ToStr(unrollList).c_str());
    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");
    ev.Print("USE_SPRAY"      , useSpray         , "%s per CU", useSpray ? "All targets" : "One target");
    ev.Print("VERBOSE"        , verbose          , verbose ? "Display test results" : "Display summary only");
    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 (useSpray && numDsts > 1) {
    printf("[ERROR] Cannot use USE_SPRAY with multiple destination buffers\n");
    exit(1);
  }

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

  std::vector<Transfer> transfers;

  int targetCount = 0;
  if (!useSpray) {
    // Each CU will work on just one target
    for (int i = 0; i < numGpus; i++) {
      targetCount = 0;
      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;
        targetCount++;
        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;
        transfers.push_back(transfer);
      }
    }
  } else {
    // Each CU will work on all targets
    for (int i = 0; i < numGpus; i++) {
      TransferBench::Transfer transfer;
      transfer.numBytes = numBytesPerTransfer;
      transfer.exeDevice = {exeType, i};
      transfer.exeSubIndex = -1;
      targetCount = 0;
      for (int j = 0; j < numGpus; j++) {
        // Check whether or not to transfer to this GPU
        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
        }
        targetCount++;
        for (int x = 0; x < numSrcs; x++) transfer.srcs.push_back({memType, useRemoteRead ? j : i});

        if (numDsts) transfer.dsts.push_back({memType, j});
        for (int x = 1; x < numDsts; x++) transfer.dsts.push_back({memType, i});
      }
      transfers.push_back(transfer);
    }
  }

  printf("GPU-GFX All-To-All Sweep benchmark:\n");
  printf("==========================\n");
  printf("- Copying %lu bytes between %s pairs of GPUs\n", numBytesPerTransfer, a2aDirect ? "directly connected" : "all");
  if (transfers.size() == 0) {
    printf("[WARN} No transfers requested. Try adjusting A2A_DIRECT or A2A_LOCAL\n");
    return;
  }

  // Execute Transfers
  TransferBench::ConfigOptions cfg = ev.ToConfigOptions();

  // Run tests
  std::map<std::pair<int, int>, TransferBench::TestResults> results;

  // Display summary
  for (int blockSize : blockList) {
    printf("Blocksize: %d\n", blockSize);
    ev.gfxBlockSize = cfg.gfx.blockSize = blockSize;

    printf("#CUs\\Unroll");
    for (int u : unrollList) {
      printf("  %d(Min) ", u);
      if (!showMinOnly) printf("  %d(Max) ", u);
    }
    printf("\n");
    for (int c : numCusList) {
      printf("   %5d   ", c);  fflush(stdout);
      for (int u : unrollList) {
        ev.gfxUnroll = cfg.gfx.unrollFactor = u;
        for (auto& transfer : transfers)
          transfer.numSubExecs = useSpray ? (c * targetCount) : c;

        double minBandwidth = std::numeric_limits<double>::max();
        double maxBandwidth = std::numeric_limits<double>::min();
        TransferBench::TestResults result;
        if (TransferBench::RunTransfers(cfg, transfers, result)) {
          for (auto const& exeResult : result.exeResults) {
            minBandwidth = std::min(minBandwidth, exeResult.second.avgBandwidthGbPerSec);
            maxBandwidth = std::max(maxBandwidth, exeResult.second.avgBandwidthGbPerSec);
          }
          if (useSpray) {
            minBandwidth *= targetCount;
            maxBandwidth *= targetCount;
          }
          results[std::make_pair(c,u)] = result;
        } else {
          minBandwidth = 0.0;
        }
        printf(" %7.2f ", minBandwidth);
        if (!showMinOnly) printf(" %7.2f ", maxBandwidth);
        fflush(stdout);
      }
      printf("\n"); fflush(stdout);
    }

    if (verbose) {
      int testNum = 0;
      for (int c : numCusList) {
        for (int u : unrollList) {
          printf("CUs: %d Unroll %d\n", c, u);
          PrintResults(ev, ++testNum, transfers, results[std::make_pair(c,u)]);
        }
      }
    }
  }
}