[SYCL] Add basic features for QuantileHistMaker (#10174)

---------

Co-authored-by: Dmitry Razdoburdin <>

tests/cpp/plugin/test_sycl_quantile_hist_builder.cc

@@ -0,0 +1,55 @@
+/**
+ * Copyright 2020-2024 by XGBoost contributors
+ */
+#include <gtest/gtest.h>
+
+#pragma GCC diagnostic push
+#pragma GCC diagnostic ignored "-Wtautological-constant-compare"
+#pragma GCC diagnostic ignored "-W#pragma-messages"
+#include <xgboost/json.h>
+#include <xgboost/task.h>
+#include "../../../plugin/sycl/tree/updater_quantile_hist.h"       // for QuantileHistMaker
+#pragma GCC diagnostic pop
+
+namespace xgboost::sycl::tree {
+TEST(SyclQuantileHistMaker, Basic) {
+  Context ctx;
+  ctx.UpdateAllowUnknown(Args{{"device", "sycl"}});
+
+  ObjInfo task{ObjInfo::kRegression};
+  std::unique_ptr<TreeUpdater> updater{TreeUpdater::Create("grow_quantile_histmaker_sycl", &ctx, &task)};
+
+  ASSERT_EQ(updater->Name(), "grow_quantile_histmaker_sycl");
+}
+
+TEST(SyclQuantileHistMaker, JsonIO) {
+  Context ctx;
+  ctx.UpdateAllowUnknown(Args{{"device", "sycl"}});
+
+  ObjInfo task{ObjInfo::kRegression};
+  Json config {Object()};
+  {
+    std::unique_ptr<TreeUpdater> updater{TreeUpdater::Create("grow_quantile_histmaker_sycl", &ctx, &task)};
+    updater->Configure({{"max_depth", std::to_string(42)}});
+    updater->Configure({{"single_precision_histogram", std::to_string(true)}});
+    updater->SaveConfig(&config);
+  }
+
+  {
+    std::unique_ptr<TreeUpdater> updater{TreeUpdater::Create("grow_quantile_histmaker_sycl", &ctx, &task)};
+    updater->LoadConfig(config);
+
+    Json new_config {Object()};
+    updater->SaveConfig(&new_config);
+
+    ASSERT_EQ(config, new_config);
+
+    auto max_depth = atoi(get<String const>(new_config["train_param"]["max_depth"]).c_str());
+    ASSERT_EQ(max_depth, 42);
+
+    auto single_precision_histogram = atoi(get<String const>(new_config["sycl_hist_train_param"]["single_precision_histogram"]).c_str());
+    ASSERT_EQ(single_precision_histogram, 1);
+  }
+  
+}
+}  // namespace xgboost::sycl::tree