[Mlir-commits] [mlir] [mlir][ExecutionEngine] Add LevelZeroRuntimeWrapper. (PR #151038)

[Petr Kurapov]

================
@@ -0,0 +1,491 @@
+//===- LevelZeroRuntimeWrappers.cpp - MLIR Level Zero (L0) wrapper library-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// Implements wrappers around the Level Zero (L0) runtime library with C linkage
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/ADT/Twine.h"
+
+#include "level_zero/ze_api.h"
+#include <cassert>
+#include <deque>
+#include <exception>
+#include <functional>
+#include <iostream>
+#include <limits>
+#include <unordered_set>
+#include <vector>
+
+namespace {
+
+template <typename F>
+auto catchAll(F &&func) {
+  try {
+    return func();
+  } catch (const std::exception &e) {
+    std::cerr << "An exception was thrown: " << e.what() << std::endl;
+    std::abort();
+  } catch (...) {
+    std::cerr << "An unknown exception was thrown." << std::endl;
+    std::abort();
+  }
+}
+
+#define L0_SAFE_CALL(call)                                                     \
+  {                                                                            \
+    ze_result_t status = (call);                                               \
+    if (status != ZE_RESULT_SUCCESS) {                                         \
+      std::cerr << "L0 error " << status << std::endl;                         \
+      std::abort();                                                            \
+    }                                                                          \
+  }
+
+} // namespace
+
+//===----------------------------------------------------------------------===//
+// L0 RT context & device setters
+//===----------------------------------------------------------------------===//
+
+// Returns the L0 driver handle for the given index. Default index is 0
+// (i.e., returns the first driver handle of the available drivers).
+
+static ze_driver_handle_t getDriver(uint32_t idx = 0) {
+  ze_init_driver_type_desc_t driver_type = {};
+  driver_type.stype = ZE_STRUCTURE_TYPE_INIT_DRIVER_TYPE_DESC;
+  driver_type.flags = ZE_INIT_DRIVER_TYPE_FLAG_GPU;
+  driver_type.pNext = nullptr;
+  uint32_t driverCount{0};
+  thread_local static std::vector<ze_driver_handle_t> drivers;
+
+  thread_local static bool isDriverInitialised{false};
+  if (isDriverInitialised)
+    return drivers[idx];
+  L0_SAFE_CALL(zeInitDrivers(&driverCount, nullptr, &driver_type));
+  if (!driverCount)
+    throw std::runtime_error("No L0 drivers found.");
+  drivers.resize(driverCount);
+  L0_SAFE_CALL(zeInitDrivers(&driverCount, drivers.data(), &driver_type));
+  if (idx >= driverCount)
+    throw std::runtime_error((llvm::Twine("Requested driver idx out-of-bound, "
+                                          "number of availabe drivers: ") +
+                              std::to_string(driverCount))
+                                 .str());
+  isDriverInitialised = true;
+  return drivers[idx];
+}
+
+static ze_device_handle_t getDefaultDevice(const uint32_t driverIdx = 0,
+                                           const int32_t devIdx = 0) {
+  thread_local static ze_device_handle_t l0Device;
+  thread_local static int32_t currDevIdx{-1};
+  if (devIdx == currDevIdx)
+    return l0Device;
+  auto driver = getDriver(driverIdx);
+  uint32_t deviceCount{0};
+  L0_SAFE_CALL(zeDeviceGet(driver, &deviceCount, nullptr));
+  if (!deviceCount)
+    throw std::runtime_error(
+        "getDefaultDevice failed: did not find L0 device.");
+  if (static_cast<int>(deviceCount) < devIdx + 1)
+    throw std::runtime_error("getDefaultDevice failed: devIdx out-of-bounds.");
+  std::vector<ze_device_handle_t> devices(deviceCount);
+  L0_SAFE_CALL(zeDeviceGet(driver, &deviceCount, devices.data()));
+  l0Device = devices[devIdx];
+  currDevIdx = devIdx;
+  return l0Device;
+}
+
+// Returns the default L0 context of the defult driver.
+static ze_context_handle_t getDefaultContext() {
+  thread_local static ze_context_handle_t context;
+  thread_local static bool isContextInitialised{false};
+  if (isContextInitialised)
+    return context;
+  ze_context_desc_t ctxtDesc = {ZE_STRUCTURE_TYPE_CONTEXT_DESC, nullptr, 0};
+  auto driver = getDriver();
+  L0_SAFE_CALL(zeContextCreate(driver, &ctxtDesc, &context));
+  isContextInitialised = true;
+  return context;
+}
+
+//===----------------------------------------------------------------------===//
+// L0 RT helper structs
+//===----------------------------------------------------------------------===//
+
+struct L0RtContext {
+  ze_driver_handle_t driver{nullptr};
+  ze_device_handle_t device{nullptr};
+  ze_context_handle_t context{nullptr};
+  // Usually, one immediate command list with ordinal 0 suffices for
+  // both copy and compute ops, but leaves HW underutilized.
+  ze_command_list_handle_t immCmdListCompute{nullptr};
+  // Copy engines can be used for both memcpy and memset, but
+  // they have limitations for memset pattern size (e.g., 1 byte).
+  ze_command_list_handle_t immCmdListCopy{nullptr};
+  uint32_t copyEngineMaxMemoryFillPatternSize{-1u};
+
+  L0RtContext(const int32_t devIdx = 0)
+      : driver(getDriver()), device(getDefaultDevice(devIdx)),
+        context(getDefaultContext()) {
+    uint32_t computeEngineOrdinal = -1u, copyEngineOrdinal = -1u;
+    ze_device_properties_t deviceProperties = {};
+    L0_SAFE_CALL(zeDeviceGetProperties(device, &deviceProperties));
+    uint32_t queueGroupCount = 0;
+    L0_SAFE_CALL(zeDeviceGetCommandQueueGroupProperties(
+        device, &queueGroupCount, nullptr));
+    std::vector<ze_command_queue_group_properties_t> queueGroupProperties(
+        queueGroupCount);
+    L0_SAFE_CALL(zeDeviceGetCommandQueueGroupProperties(
+        device, &queueGroupCount, queueGroupProperties.data()));
+    for (uint32_t queueGroupIdx = 0; queueGroupIdx < queueGroupCount;
+         ++queueGroupIdx) {
+      const auto &group = queueGroupProperties[queueGroupIdx];
+      if (group.flags & ZE_COMMAND_QUEUE_GROUP_PROPERTY_FLAG_COMPUTE)
+        computeEngineOrdinal = queueGroupIdx;
+      else if (group.flags & ZE_COMMAND_QUEUE_GROUP_PROPERTY_FLAG_COPY) {
+        copyEngineOrdinal = queueGroupIdx;
+        copyEngineMaxMemoryFillPatternSize = group.maxMemoryFillPatternSize;
+      }
+      if (copyEngineOrdinal != -1u && computeEngineOrdinal != -1u)
+        break;
+    }
+    // Fallback to the default queue if no dedicated copy queue is available.
+    if (copyEngineOrdinal == -1u)
+      copyEngineOrdinal = computeEngineOrdinal;
+    assert(copyEngineOrdinal != -1u && computeEngineOrdinal != -1u &&
+           "Expected two engines to be available.");
+    ze_command_queue_desc_t cmdQueueDesc{
+        ZE_STRUCTURE_TYPE_COMMAND_QUEUE_DESC,
+        nullptr,
+        copyEngineOrdinal, // ordinal
+        0,                 // index (assume one physical engine in the group)
+        0,                 // flags
+        ZE_COMMAND_QUEUE_MODE_ASYNCHRONOUS,
+        ZE_COMMAND_QUEUE_PRIORITY_NORMAL};
+    L0_SAFE_CALL(zeCommandListCreateImmediate(context, device, &cmdQueueDesc,
+                                              &immCmdListCopy));
+    cmdQueueDesc.ordinal = computeEngineOrdinal;
+    L0_SAFE_CALL(zeCommandListCreateImmediate(context, device, &cmdQueueDesc,
+                                              &immCmdListCompute));
+  }
+  void cleanup() {
+    L0_SAFE_CALL(zeCommandListDestroy(immCmdListCopy));
----------------
kurapov-peter wrote:

+1, and if you leave it as is, there's potential for inconsistent states (e.g., user called `cleanup`, then `getDefaultContext` and got an invalid context handle.

https://github.com/llvm/llvm-project/pull/151038