Introducing DPC++-based plugin (predictor, objective function) supporting oneAPI programming model (#5825)

* Added plugin with DPC++-based predictor and objective function

* Update CMakeLists.txt

* Update regression_obj_oneapi.cc

* Added README.md for OneAPI plugin

* Added OneAPI predictor support to gbtree

* Update README.md

* Merged kernels in gradient computation. Enabled multiple loss functions with DPC++ backend

* Aligned plugin CMake files with latest master changes. Fixed whitespace typos

* Removed debug output

* [CI] Make oneapi_plugin a CMake target

* Added tests for OneAPI plugin for predictor and obj. functions

* Temporarily switched to default selector for device dispacthing in OneAPI plugin to enable execution in environments without gpus

* Updated readme file.

* Fixed USM usage in predictor

* Removed workaround with explicit templated names for DPC++ kernels

* Fixed warnings in plugin tests

* Fix CMake build of gtest

Co-authored-by: Hyunsu Cho <chohyu01@cs.washington.edu>

src/common/common.h

@@ -154,6 +154,12 @@ inline void AssertGPUSupport() {
 #endif  // XGBOOST_USE_CUDA
 }
 
+inline void AssertOneAPISupport() {
+#ifndef XGBOOST_USE_ONEAPI
+    LOG(FATAL) << "XGBoost version not compiled with OneAPI support.";
+#endif  // XGBOOST_USE_ONEAPI
+}
+
 }  // namespace common
 }  // namespace xgboost
 #endif  // XGBOOST_COMMON_COMMON_H_

src/gbm/gbtree.cc

@@ -62,6 +62,14 @@ void GBTree::Configure(const Args& cfg) {
   }
 #endif  // defined(XGBOOST_USE_CUDA)
 
+#if defined(XGBOOST_USE_ONEAPI)
+  if (!oneapi_predictor_) {
+    oneapi_predictor_ = std::unique_ptr<Predictor>(
+        Predictor::Create("oneapi_predictor", this->generic_param_));
+  }
+  oneapi_predictor_->Configure(cfg);
+#endif  // defined(XGBOOST_USE_ONEAPI)
+
   monitor_.Init("GBTree");
 
   specified_updater_ = std::any_of(cfg.cbegin(), cfg.cend(),
@@ -413,6 +421,14 @@ GBTree::GetPredictor(HostDeviceVector<float> const *out_pred,
 #else
       common::AssertGPUSupport();
 #endif  // defined(XGBOOST_USE_CUDA)
+    }
+    if (tparam_.predictor == PredictorType::kOneAPIPredictor) {
+#if defined(XGBOOST_USE_ONEAPI)
+      CHECK(oneapi_predictor_);
+      return oneapi_predictor_;
+#else
+      common::AssertOneAPISupport();
+#endif  // defined(XGBOOST_USE_ONEAPI)
     }
     CHECK(cpu_predictor_);
     return cpu_predictor_;

src/gbm/gbtree.h

@@ -45,7 +45,8 @@ enum class TreeProcessType : int {
 enum class PredictorType : int {
   kAuto = 0,
   kCPUPredictor,
-  kGPUPredictor
+  kGPUPredictor,
+  kOneAPIPredictor
 };
 }  // namespace xgboost
 
@@ -93,6 +94,7 @@ struct GBTreeTrainParam : public XGBoostParameter<GBTreeTrainParam> {
         .add_enum("auto", PredictorType::kAuto)
         .add_enum("cpu_predictor", PredictorType::kCPUPredictor)
         .add_enum("gpu_predictor", PredictorType::kGPUPredictor)
+        .add_enum("oneapi_predictor", PredictorType::kOneAPIPredictor)
         .describe("Predictor algorithm type");
     DMLC_DECLARE_FIELD(tree_method)
         .set_default(TreeMethod::kAuto)
@@ -292,6 +294,9 @@ class GBTree : public GradientBooster {
 #if defined(XGBOOST_USE_CUDA)
   std::unique_ptr<Predictor> gpu_predictor_;
 #endif  // defined(XGBOOST_USE_CUDA)
+#if defined(XGBOOST_USE_ONEAPI)
+  std::unique_ptr<Predictor> oneapi_predictor_;
+#endif  // defined(XGBOOST_USE_ONEAPI)
   common::Monitor monitor_;
 };