Add quickreduce as alternative to custom allreduce

CMakeLists.txt

@@ -638,6 +638,14 @@ if(VLLM_GPU_LANG STREQUAL "CUDA")
 # if CUDA endif
 endif()
 
+if (VLLM_GPU_LANG STREQUAL "HIP")
+  # Add QuickReduce kernels
+  list(APPEND VLLM_EXT_SRC
+    "csrc/custom_quickreduce.cu"
+  )
+# if ROCM endif
+endif()
+
 message(STATUS "Enabling C extension.")
 define_gpu_extension_target(
   _C

csrc/custom_quickreduce.cu

@@ -0,0 +1,86 @@
+#include <ATen/cuda/Exceptions.h>
+#include <c10/cuda/CUDAGuard.h>
+#include <c10/cuda/CUDAStream.h>
+#include <torch/all.h>
+
+#ifdef USE_ROCM
+
+  #include "quickreduce/quick_reduce.h"
+
+quickreduce::fptr_t init_custom_qr(int64_t rank, int64_t world_size) {
+  if (world_size > 8)
+    throw std::invalid_argument("world size > 8 is not supported");
+  if (world_size == 6)
+    throw std::invalid_argument("world size == 6 is not supported");
+  if (world_size % 2 != 0)
+    throw std::invalid_argument("Odd num gpus is not supported for now");
+  if (rank < 0 || rank >= world_size)
+    throw std::invalid_argument("invalid rank passed in");
+  quickreduce::DeviceComms* fptr = new quickreduce::DeviceComms();
+  fptr->init(world_size, rank);
+  return (quickreduce::fptr_t)fptr;
+}
+
+void qr_destroy(quickreduce::fptr_t _fa) {
+  if (_fa) {
+    auto fa = reinterpret_cast<quickreduce::DeviceComms*>(_fa);
+    fa->destroy();
+    delete fa;
+  }
+}
+
+torch::Tensor qr_get_handle(quickreduce::fptr_t _fa) {
+  auto fa = reinterpret_cast<quickreduce::DeviceComms*>(_fa);
+  hipIpcMemHandle_t handle = fa->get_handle();
+  auto device_index = c10::cuda::current_device();
+  auto options =
+      torch::TensorOptions().dtype(torch::kUInt8).device(torch::kCPU);
+  auto data_handle =
+      torch::empty({static_cast<int64_t>(sizeof(hipIpcMemHandle_t))}, options);
+  std::memcpy(data_handle.data_ptr(), &handle, sizeof(hipIpcMemHandle_t));
+  return data_handle;
+}
+
+void qr_open_handles(quickreduce::fptr_t _fa,
+                     const std::vector<torch::Tensor>& handles) {
+  auto fa = reinterpret_cast<quickreduce::DeviceComms*>(_fa);
+  std::vector<hipIpcMemHandle_t> ipc_handles;
+  ipc_handles.reserve(handles.size());
+  for (auto& handle : handles) {
+    // Ensure the tensor is on the same device as the current device.
+    hipIpcMemHandle_t ipc_handle;
+    std::memcpy(&ipc_handle, handle.data_ptr(), sizeof(hipIpcMemHandle_t));
+    ipc_handles.push_back(ipc_handle);
+  }
+  fa->open_ipc_handles(ipc_handles);
+}
+
+void qr_all_reduce(quickreduce::fptr_t _fa, torch::Tensor& inp,
+                   torch::Tensor& out, int64_t quant_level) {
+  auto fa = reinterpret_cast<quickreduce::DeviceComms*>(_fa);
+  const at::cuda::OptionalCUDAGuard device_guard(device_of(inp));
+  auto stream = at::cuda::getCurrentHIPStreamMasqueradingAsCUDA();
+
+  TORCH_CHECK_EQ(inp.scalar_type(), out.scalar_type());
+  TORCH_CHECK_EQ(inp.numel(), out.numel());
+  TORCH_CHECK_LE(out.numel(), quickreduce::DeviceComms::kMaxProblemSize);
+  if (out.scalar_type() == at::ScalarType::Half) {
+    fa->allreduce<half>(reinterpret_cast<half*>(inp.data_ptr()),
+                        reinterpret_cast<half*>(out.data_ptr()), out.numel(),
+                        quant_level, stream);
+  } else if (out.scalar_type() == at::ScalarType::BFloat16) {
+    fa->allreduce<quickreduce::nv_bfloat16>(
+        reinterpret_cast<quickreduce::nv_bfloat16*>(inp.data_ptr()),
+        reinterpret_cast<quickreduce::nv_bfloat16*>(out.data_ptr()),
+        out.numel(), quant_level, stream);
+  } else {
+    throw std::runtime_error(
+        "quick allreduce only supports float16 and bfloat16");
+  }
+}
+
+int64_t qr_max_size() {
+  return static_cast<int64_t>(quickreduce::DeviceComms::kMaxProblemSize);
+}
+
+#endif  // USE_ROCM

csrc/ops.h

@@ -360,3 +360,13 @@ std::tuple<int64_t, torch::Tensor> allocate_shared_buffer_and_handle(
     int64_t size);
 int64_t open_mem_handle(torch::Tensor& mem_handle);
 void free_shared_buffer(int64_t buffer);
+
+#ifdef USE_ROCM
+fptr_t init_custom_qr(int64_t rank, int64_t world_size);
+void qr_destroy(fptr_t _fa);
+torch::Tensor qr_get_handle(fptr_t _fa);
+void qr_open_handles(fptr_t _fa, const std::vector<torch::Tensor>& handles);
+void qr_all_reduce(fptr_t _fa, torch::Tensor& inp, torch::Tensor& out,
+                   int64_t quant_level);
+int64_t qr_max_size();
+#endif