bench swap, is already fast

test/bench/copy.cpp

@@ -1,13 +1,10 @@
 #include <ankerl/unordered_dense.h>
-#include <app/name_of_type.h>
 #include <app/nanobench.h>
 #include <app/robin_hood.h>
 
-#include <chrono>
 #include <doctest.h>
 #include <fmt/format.h>
 
-#include <array>
 #include <unordered_map>
 
 template <typename Map>

test/bench/swap.cpp

@@ -0,0 +1,48 @@
+#include <ankerl/unordered_dense.h>
+#include <app/nanobench.h>
+#include <app/robin_hood.h>
+
+#include <cstdint>
+#include <doctest.h>
+#include <fmt/format.h>
+
+#include <iostream>
+#include <unordered_map>
+
+namespace {
+
+template <typename Map>
+void bench(std::string_view name) {
+    Map a;
+    Map b;
+    ankerl::nanobench::Rng rng(123);
+
+    ankerl::nanobench::Bench bench;
+    for (size_t j = 0; j < 10000; ++j) {
+        a[rng()];
+        b[rng()];
+    }
+    bench.run(fmt::format("swap {}", name), [&] {
+        std::swap(a, b);
+    });
+    ankerl::nanobench::doNotOptimizeAway(&a);
+    ankerl::nanobench::doNotOptimizeAway(&b);
+}
+
+} // namespace
+
+TEST_CASE("bench_swap_rhn" * doctest::test_suite("bench") * doctest::skip()) {
+    bench<robin_hood::unordered_node_map<uint64_t, uint64_t>>("robin_hood::unordered_node_map");
+}
+
+TEST_CASE("bench_swap_rhf" * doctest::test_suite("bench") * doctest::skip()) {
+    bench<robin_hood::unordered_flat_map<uint64_t, uint64_t>>("robin_hood::unordered_flat_map");
+}
+
+TEST_CASE("bench_swap_std" * doctest::test_suite("bench") * doctest::skip()) {
+    bench<std::unordered_map<uint64_t, uint64_t>>("std::unordered_map");
+}
+
+TEST_CASE("bench_swap_udm" * doctest::test_suite("bench") * doctest::skip()) {
+    bench<ankerl::unordered_dense::map<uint64_t, uint64_t>>("ankerl::unordered_dense::map");
+}

test/meson.build

@@ -5,6 +5,7 @@ test_sources = [
     'bench/copy.cpp',
     'bench/find_random.cpp',
     'bench/quick_overall_map.cpp',
+    'bench/swap.cpp',
     'unit/assign_to_move.cpp',
     'unit/assignment_combinations.cpp',
     'unit/at.cpp',