merge(3p/immer): Subtree merge at 'ad3e3556d' as 'third_party/immer'

Change-Id: I9636a41ad44b4218293833fd3e9456d9b07c731b

third_party/immer/benchmark/extra/refcounting.cpp

@@ -0,0 +1,146 @@
+//
+// immer: immutable data structures for C++
+// Copyright (C) 2016, 2017, 2018 Juan Pedro Bolivar Puente
+//
+// This software is distributed under the Boost Software License, Version 1.0.
+// See accompanying file LICENSE or copy at http://boost.org/LICENSE_1_0.txt
+//
+
+#include <immer/detail/ref_count_base.hpp>
+
+#include <nonius.h++>
+#include <boost/intrusive_ptr.hpp>
+
+#include <atomic>
+#include <cstdlib>
+#include <iterator>
+#include <memory>
+#include <utility>
+#include <array>
+#include <vector>
+
+NONIUS_PARAM(N, std::size_t{1000})
+
+constexpr auto benchmark_size = 32u;
+
+struct object_t : immer::detail::ref_count_base<object_t>
+{};
+
+auto make_data()
+{
+    auto objs = std::array<std::unique_ptr<object_t>, benchmark_size>();
+    std::generate(objs.begin(), objs.end(), [] {
+        return std::make_unique<object_t>();
+    });
+    auto refs = std::array<object_t*, benchmark_size>();
+    std::transform(objs.begin(), objs.end(), refs.begin(), [](auto& obj) {
+        return obj.get();
+    });
+    return make_pair(std::move(objs),
+                     std::move(refs));
+}
+
+NONIUS_BENCHMARK("intrusive_ptr", [] (nonius::chronometer meter)
+{
+    auto arr     = std::array<boost::intrusive_ptr<object_t>, benchmark_size>{};
+    auto storage = std::vector<
+        nonius::storage_for<
+            std::array<boost::intrusive_ptr<object_t>, benchmark_size>>> (
+                meter.runs());
+    std::generate(arr.begin(), arr.end(), [] {
+        return new object_t{};
+    });
+    meter.measure([&] (int i) {
+        storage[i].construct(arr);
+    });
+})
+
+NONIUS_BENCHMARK("generic", [] (nonius::chronometer meter)
+{
+    auto data = make_data();
+    auto& refs = data.second;
+    object_t* r[benchmark_size];
+
+    meter.measure([&] {
+        std::transform(refs.begin(), refs.end(), r, [] (auto& p) {
+            if (p) p->ref_count.fetch_add(1, std::memory_order_relaxed);
+            return p;
+        });
+        return r;
+    });
+})
+
+NONIUS_BENCHMARK("manual", [] (nonius::chronometer meter)
+{
+    auto data = make_data();
+    auto& refs = data.second;
+    object_t* r[benchmark_size];
+
+    meter.measure([&] {
+        for (auto& p : refs)
+            if (p) p->ref_count.fetch_add(1, std::memory_order_relaxed);
+        std::copy(refs.begin(), refs.end(), r);
+        return r;
+    });
+})
+
+NONIUS_BENCHMARK("manual - unroll", [] (nonius::chronometer meter)
+{
+    auto data = make_data();
+    auto& refs = data.second;
+    object_t* r[benchmark_size];
+
+    meter.measure([&] {
+        auto e = refs.end();
+        for (auto p = refs.begin(); p != e;) {
+            (*p++)->ref_count.fetch_add(1, std::memory_order_relaxed);
+            (*p++)->ref_count.fetch_add(1, std::memory_order_relaxed);
+            (*p++)->ref_count.fetch_add(1, std::memory_order_relaxed);
+            (*p++)->ref_count.fetch_add(1, std::memory_order_relaxed);
+        }
+        std::copy(refs.begin(), refs.end(), r);
+        return r;
+    });
+})
+
+NONIUS_BENCHMARK("manual - nocheck", [] (nonius::chronometer meter)
+{
+    auto data = make_data();
+    auto& refs = data.second;
+    object_t* r[benchmark_size];
+
+    meter.measure([&] {
+        for (auto& p : refs)
+            p->ref_count.fetch_add(1, std::memory_order_relaxed);
+        std::copy(refs.begin(), refs.end(), r);
+        return r;
+    });
+})
+
+NONIUS_BENCHMARK("manual - constant", [] (nonius::chronometer meter)
+{
+    auto data = make_data();
+    auto& refs = data.second;
+    object_t* r[benchmark_size];
+
+    meter.measure([&] {
+        for (auto i = 0u; i < benchmark_size; ++i)
+            refs[i]->ref_count.fetch_add(1, std::memory_order_relaxed);
+        std::copy(refs.begin(), refs.end(), r);
+        return r;
+    });
+})
+
+NONIUS_BENCHMARK("manual - memcopy", [] (nonius::chronometer meter)
+{
+    auto data = make_data();
+    auto& refs = data.second;
+    object_t* r[benchmark_size];
+
+    meter.measure([&] {
+        for (auto& p : refs)
+            if (p) p->ref_count.fetch_add(1, std::memory_order_relaxed);
+        std::memcpy(r, &refs[0], sizeof(object_t*) * benchmark_size);
+        return r;
+    });
+})