Add groupby nunique aggregation benchmark (NVIDIA#11472)

This adds a simple benchmark for groupby `nunique` aggregation.

Authors:
  - Nghia Truong (https://github.com/ttnghia)

Approvers:
  - Bradley Dice (https://github.com/bdice)
  - Tobias Ribizel (https://github.com/upsj)

URL: rapidsai/cudf#11472

cpp/benchmarks/CMakeLists.txt

@@ -200,7 +200,8 @@ ConfigureBench(
 )
 
 ConfigureNVBench(
-  GROUPBY_NVBENCH groupby/group_max.cpp groupby/group_rank.cpp groupby/group_struct_keys.cpp
+  GROUPBY_NVBENCH groupby/group_max.cpp groupby/group_nunique.cpp groupby/group_rank.cpp
+  groupby/group_struct_keys.cpp
 )
 
 # ##################################################################################################

cpp/benchmarks/groupby/group_nunique.cpp

@@ -0,0 +1,85 @@
+/*
+ * Copyright (c) 2022, NVIDIA CORPORATION.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <benchmarks/common/generate_input.hpp>
+#include <benchmarks/fixture/rmm_pool_raii.hpp>
+
+#include <cudf/groupby.hpp>
+
+#include <nvbench/nvbench.cuh>
+
+namespace {
+
+template <typename... Args>
+auto make_aggregation_request_vector(cudf::column_view const& values, Args&&... args)
+{
+  std::vector<std::unique_ptr<cudf::groupby_aggregation>> aggregations;
+  (aggregations.emplace_back(std::forward<Args>(args)), ...);
+
+  std::vector<cudf::groupby::aggregation_request> requests;
+  requests.emplace_back(cudf::groupby::aggregation_request{values, std::move(aggregations)});
+
+  return requests;
+}
+
+}  // namespace
+
+template <typename Type>
+void bench_groupby_nunique(nvbench::state& state, nvbench::type_list<Type>)
+{
+  cudf::rmm_pool_raii pool_raii;
+  const auto size = static_cast<cudf::size_type>(state.get_int64("num_rows"));
+
+  auto const keys_table = [&] {
+    data_profile profile;
+    profile.set_null_frequency(std::nullopt);
+    profile.set_cardinality(0);
+    profile.set_distribution_params<int32_t>(
+      cudf::type_to_id<int32_t>(), distribution_id::UNIFORM, 0, 100);
+    return create_random_table({cudf::type_to_id<int32_t>()}, row_count{size}, profile);
+  }();
+
+  auto const vals_table = [&] {
+    data_profile profile;
+    if (const auto null_freq = state.get_float64("null_frequency"); null_freq > 0) {
+      profile.set_null_frequency({null_freq});
+    } else {
+      profile.set_null_frequency(std::nullopt);
+    }
+    profile.set_cardinality(0);
+    profile.set_distribution_params<Type>(cudf::type_to_id<Type>(),
+                                          distribution_id::UNIFORM,
+                                          static_cast<Type>(0),
+                                          static_cast<Type>(1000));
+    return create_random_table({cudf::type_to_id<Type>()}, row_count{size}, profile);
+  }();
+
+  auto const& keys = keys_table->get_column(0);
+  auto const& vals = vals_table->get_column(0);
+
+  auto gb_obj         = cudf::groupby::groupby(cudf::table_view({keys, keys, keys}));
+  auto const requests = make_aggregation_request_vector(
+    vals, cudf::make_nunique_aggregation<cudf::groupby_aggregation>());
+
+  state.set_cuda_stream(nvbench::make_cuda_stream_view(cudf::default_stream_value.value()));
+  state.exec(nvbench::exec_tag::sync,
+             [&](nvbench::launch& launch) { auto const result = gb_obj.aggregate(requests); });
+}
+
+NVBENCH_BENCH_TYPES(bench_groupby_nunique, NVBENCH_TYPE_AXES(nvbench::type_list<int32_t, int64_t>))
+  .set_name("groupby_nunique")
+  .add_int64_power_of_two_axis("num_rows", {12, 16, 20, 24})
+  .add_float64_axis("null_frequency", {0, 0.5});