Add "reserved" benchmark for preallocated vector

Author: patrickroberts

tests/beman/any_view/CMakeLists.txt

@@ -29,8 +29,8 @@ function(beman_add_test)
     gtest_discover_tests(${target})
 endfunction()
 
-beman_add_benchmark(TARGET all SOURCES all.benchmark.cpp detail/eager.cpp detail/fused.cpp detail/lazy.cpp detail/products.cpp)
-beman_add_benchmark(TARGET take SOURCES take.benchmark.cpp detail/eager.cpp detail/fused.cpp detail/lazy.cpp detail/products.cpp)
+beman_add_benchmark(TARGET all SOURCES all.benchmark.cpp detail/eager.cpp detail/fused.cpp detail/lazy.cpp detail/products.cpp detail/reserved.cpp)
+beman_add_benchmark(TARGET take SOURCES take.benchmark.cpp detail/eager.cpp detail/fused.cpp detail/lazy.cpp detail/products.cpp detail/reserved.cpp)
 
 beman_add_test(TARGET concepts SOURCES concepts.test.cpp)
 beman_add_test(TARGET constexpr SOURCES constexpr.test.cpp)

tests/beman/any_view/all.benchmark.cpp

@@ -4,6 +4,7 @@
 #include "detail/fused.hpp"
 #include "detail/lazy.hpp"
 #include "detail/products.hpp"
+#include "detail/reserved.hpp"
 
 #include <benchmark/benchmark.h>
 
@@ -57,8 +58,22 @@ static void BM_all_lazy(benchmark::State& state) {
     }
 }
 
+static void BM_all_reserved(benchmark::State& state) {
+    const auto size  = state.range(0);
+    const auto begin = global_products.begin();
+
+    reserved::database db{.products = {begin, begin + size}};
+
+    for (auto _ : state) {
+        for (std::string_view name : db.get_products({.min_quantity = 10})) {
+            use(name);
+        }
+    }
+}
+
 BENCHMARK(BM_all_eager)->RangeMultiplier(2)->Range(1 << 10, max_size);
 BENCHMARK(BM_all_fused)->RangeMultiplier(2)->Range(1 << 10, max_size);
 BENCHMARK(BM_all_lazy)->RangeMultiplier(2)->Range(1 << 10, max_size);
+BENCHMARK(BM_all_reserved)->RangeMultiplier(2)->Range(1 << 10, max_size);
 
 BENCHMARK_MAIN();

tests/beman/any_view/detail/eager.cpp

@@ -7,7 +7,7 @@ auto eager::database::get_products(query_t query) const -> names_t {
 
     for (const auto& product : products) {
         if (product.quantity >= query.min_quantity) {
-            results.push_back(product.name);
+            results.emplace_back(product.name);
         }
     }
 

tests/beman/any_view/detail/reserved.cpp

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#include "reserved.hpp"
+
+#include <algorithm>
+
+auto reserved::database::get_products(query_t query) const -> names_t {
+    const auto capacity = std::ranges::count_if(
+        products, [=](const product_t& product) -> bool { return product.quantity >= query.min_quantity; });
+
+    names_t results;
+    results.reserve(capacity);
+
+    for (const auto& product : products) {
+        if (product.quantity >= query.min_quantity) {
+            results.emplace_back(product.name);
+        }
+    }
+
+    return results;
+}

tests/beman/any_view/detail/reserved.hpp

@@ -0,0 +1,19 @@
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+
+#pragma once
+
+#include "product.hpp"
+
+#include <vector>
+
+namespace reserved {
+
+using names_t = std::vector<std::string_view>;
+
+struct database {
+    std::vector<product_t> products;
+
+    auto get_products(query_t) const -> names_t;
+};
+
+} // namespace reserved

tests/beman/any_view/take.benchmark.cpp

@@ -4,6 +4,7 @@
 #include "detail/fused.hpp"
 #include "detail/lazy.hpp"
 #include "detail/products.hpp"
+#include "detail/reserved.hpp"
 
 #include <benchmark/benchmark.h>
 
@@ -57,8 +58,22 @@ static void BM_take_lazy(benchmark::State& state) {
     }
 }
 
+static void BM_take_reserved(benchmark::State& state) {
+    const auto size  = state.range(0);
+    const auto begin = global_products.begin();
+
+    reserved::database db{.products = {begin, begin + size}};
+
+    for (auto _ : state) {
+        for (std::string_view name : db.get_products({.min_quantity = 10}) | std::views::take(100)) {
+            use(name);
+        }
+    }
+}
+
 BENCHMARK(BM_take_eager)->RangeMultiplier(2)->Range(1 << 10, max_size);
 BENCHMARK(BM_take_fused)->RangeMultiplier(2)->Range(1 << 10, max_size);
 BENCHMARK(BM_take_lazy)->RangeMultiplier(2)->Range(1 << 10, max_size);
+BENCHMARK(BM_take_reserved)->RangeMultiplier(2)->Range(1 << 10, max_size);
 
 BENCHMARK_MAIN();