From 161b4811d5382627e09c0538cf84d9c109688fc5 Mon Sep 17 00:00:00 2001
From: Mark de Wever <koraq@xs4all.nl>
Date: Sat, 30 Mar 2024 17:35:56 +0100
Subject: [PATCH] [libc++][format][1/7] Adds more benchmarks.

This patch is the start of a series to improve the speed of std::format,
std::format_to, std::format_to_n, and std::formatted_size.

This is mostly achieved by changing the __output_buffer class. This new
__output_buffer class also makes it easier to implement buffering for
P3107R5 "Permit an efficient implementation of std::print"
---
 libcxx/test/benchmarks/CMakeLists.txt         |   3 +
 libcxx/test/benchmarks/format.bench.cpp       |   6 +-
 .../format/write_double_comparison.bench.cpp  | 117 ++++++++++
 .../format/write_int_comparison.bench.cpp     | 117 ++++++++++
 .../format/write_string_comparison.bench.cpp  | 221 ++++++++++++++++++
 5 files changed, 462 insertions(+), 2 deletions(-)
 create mode 100644 libcxx/test/benchmarks/format/write_double_comparison.bench.cpp
 create mode 100644 libcxx/test/benchmarks/format/write_int_comparison.bench.cpp
 create mode 100644 libcxx/test/benchmarks/format/write_string_comparison.bench.cpp

diff --git a/libcxx/test/benchmarks/CMakeLists.txt b/libcxx/test/benchmarks/CMakeLists.txt
index 616cf0ff8d237..b402af8d80dae 100644
--- a/libcxx/test/benchmarks/CMakeLists.txt
+++ b/libcxx/test/benchmarks/CMakeLists.txt
@@ -147,6 +147,9 @@ set(BENCHMARK_TESTS
     deque_iterator.bench.cpp
     exception_ptr.bench.cpp
     filesystem.bench.cpp
+    format/write_double_comparison.bench.cpp
+    format/write_int_comparison.bench.cpp
+    format/write_string_comparison.bench.cpp
     format_to_n.bench.cpp
     format_to.bench.cpp
     format.bench.cpp
diff --git a/libcxx/test/benchmarks/format.bench.cpp b/libcxx/test/benchmarks/format.bench.cpp
index 17eaccb18ee1c..22f369f0d3be0 100644
--- a/libcxx/test/benchmarks/format.bench.cpp
+++ b/libcxx/test/benchmarks/format.bench.cpp
@@ -20,8 +20,10 @@ static void BM_format_string(benchmark::State& state) {
   size_t size = state.range(0);
   std::basic_string<CharT> str(size, CharT('*'));
 
-  while (state.KeepRunningBatch(str.size()))
-    benchmark::DoNotOptimize(std::format(CSTR("{}"), str));
+  while (state.KeepRunningBatch(str.size())) {
+    std::basic_string<CharT> s = std::format(CSTR("{}"), str);
+    benchmark::DoNotOptimize(s);
+  }
 
   state.SetBytesProcessed(state.iterations() * size * sizeof(CharT));
 }
diff --git a/libcxx/test/benchmarks/format/write_double_comparison.bench.cpp b/libcxx/test/benchmarks/format/write_double_comparison.bench.cpp
new file mode 100644
index 0000000000000..93db5f1f5f456
--- /dev/null
+++ b/libcxx/test/benchmarks/format/write_double_comparison.bench.cpp
@@ -0,0 +1,117 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <array>
+#include <charconv>
+#include <cstdio>
+#include <format>
+#include <iterator>
+#include <list>
+#include <random>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+
+std::array data = [] {
+  std::uniform_real_distribution<double> distribution;
+  std::mt19937 generator;
+  std::array<double, 1000> result;
+  std::generate_n(result.begin(), result.size(), [&] { return distribution(generator); });
+  return result;
+}();
+
+static void BM_sprintf(benchmark::State& state) {
+  std::array<char, 100> output;
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      sprintf(output.data(), "%f", value);
+      benchmark::DoNotOptimize(output.data());
+    }
+}
+
+static void BM_to_string(benchmark::State& state) {
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::string s = std::to_string(value);
+      benchmark::DoNotOptimize(s);
+    }
+}
+
+static void BM_to_chars(benchmark::State& state) {
+  std::array<char, 100> output;
+
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::to_chars(output.data(), output.data() + output.size(), value);
+      benchmark::DoNotOptimize(output.data());
+    }
+}
+
+static void BM_to_chars_as_string(benchmark::State& state) {
+  std::array<char, 100> output;
+
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      char* end = std::to_chars(output.data(), output.data() + output.size(), value).ptr;
+      std::string s{output.data(), end};
+      benchmark::DoNotOptimize(s);
+    }
+}
+
+static void BM_format(benchmark::State& state) {
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::string s = std::format("{}", value);
+      benchmark::DoNotOptimize(s);
+    }
+}
+
+template <class C>
+static void BM_format_to_back_inserter(benchmark::State& state) {
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      C c;
+      std::format_to(std::back_inserter(c), "{}", value);
+      benchmark::DoNotOptimize(c);
+    }
+}
+
+template <class F>
+static void BM_format_to_iterator(benchmark::State& state, F&& f) {
+  auto output = f();
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::format_to(std::begin(output), "{}", value);
+      benchmark::DoNotOptimize(std::begin(output));
+    }
+}
+
+BENCHMARK(BM_sprintf);
+BENCHMARK(BM_to_string);
+BENCHMARK(BM_to_chars);
+BENCHMARK(BM_to_chars_as_string);
+BENCHMARK(BM_format);
+BENCHMARK_TEMPLATE(BM_format_to_back_inserter, std::string);
+BENCHMARK_TEMPLATE(BM_format_to_back_inserter, std::vector<char>);
+BENCHMARK_TEMPLATE(BM_format_to_back_inserter, std::list<char>);
+BENCHMARK_CAPTURE(BM_format_to_iterator, <std::array>, ([] {
+                    std::array<char, 100> a;
+                    return a;
+                  }));
+BENCHMARK_CAPTURE(BM_format_to_iterator, <std::string>, ([] {
+                    std::string s;
+                    s.resize(100);
+                    return s;
+                  }));
+BENCHMARK_CAPTURE(BM_format_to_iterator, <std::vector>, ([] {
+                    std::vector<char> v;
+                    v.resize(100);
+                    return v;
+                  }));
+
+BENCHMARK_MAIN();
diff --git a/libcxx/test/benchmarks/format/write_int_comparison.bench.cpp b/libcxx/test/benchmarks/format/write_int_comparison.bench.cpp
new file mode 100644
index 0000000000000..835a56f036225
--- /dev/null
+++ b/libcxx/test/benchmarks/format/write_int_comparison.bench.cpp
@@ -0,0 +1,117 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <array>
+#include <charconv>
+#include <cstdio>
+#include <format>
+#include <iterator>
+#include <list>
+#include <random>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+
+std::array data = [] {
+  std::uniform_int_distribution<int> distribution{std::numeric_limits<int>::min(), std::numeric_limits<int>::max()};
+  std::mt19937 generator;
+  std::array<int, 1000> result;
+  std::generate_n(result.begin(), result.size(), [&] { return distribution(generator); });
+  return result;
+}();
+
+static void BM_sprintf(benchmark::State& state) {
+  std::array<char, 100> output;
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      sprintf(output.data(), "%d", value);
+      benchmark::DoNotOptimize(output.data());
+    }
+}
+
+static void BM_to_string(benchmark::State& state) {
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::string s = std::to_string(value);
+      benchmark::DoNotOptimize(s);
+    }
+}
+
+static void BM_to_chars(benchmark::State& state) {
+  std::array<char, 100> output;
+
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::to_chars(output.data(), output.data() + output.size(), value);
+      benchmark::DoNotOptimize(output.data());
+    }
+}
+
+static void BM_to_chars_as_string(benchmark::State& state) {
+  std::array<char, 100> output;
+
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      char* end = std::to_chars(output.data(), output.data() + output.size(), value).ptr;
+      std::string s{output.data(), end};
+      benchmark::DoNotOptimize(s);
+    }
+}
+
+static void BM_format(benchmark::State& state) {
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::string s = std::format("{}", value);
+      benchmark::DoNotOptimize(s);
+    }
+}
+
+template <class C>
+static void BM_format_to_back_inserter(benchmark::State& state) {
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      C c;
+      std::format_to(std::back_inserter(c), "{}", value);
+      benchmark::DoNotOptimize(c);
+    }
+}
+
+template <class F>
+static void BM_format_to_iterator(benchmark::State& state, F&& f) {
+  auto output = f();
+  while (state.KeepRunningBatch(data.size()))
+    for (auto value : data) {
+      std::format_to(std::begin(output), "{}", value);
+      benchmark::DoNotOptimize(std::begin(output));
+    }
+}
+
+BENCHMARK(BM_sprintf);
+BENCHMARK(BM_to_string);
+BENCHMARK(BM_to_chars);
+BENCHMARK(BM_to_chars_as_string);
+BENCHMARK(BM_format);
+BENCHMARK_TEMPLATE(BM_format_to_back_inserter, std::string);
+BENCHMARK_TEMPLATE(BM_format_to_back_inserter, std::vector<char>);
+BENCHMARK_TEMPLATE(BM_format_to_back_inserter, std::list<char>);
+BENCHMARK_CAPTURE(BM_format_to_iterator, <std::array>, ([] {
+                    std::array<char, 100> a;
+                    return a;
+                  }));
+BENCHMARK_CAPTURE(BM_format_to_iterator, <std::string>, ([] {
+                    std::string s;
+                    s.resize(100);
+                    return s;
+                  }));
+BENCHMARK_CAPTURE(BM_format_to_iterator, <std::vector>, ([] {
+                    std::vector<char> v;
+                    v.resize(100);
+                    return v;
+                  }));
+
+BENCHMARK_MAIN();
diff --git a/libcxx/test/benchmarks/format/write_string_comparison.bench.cpp b/libcxx/test/benchmarks/format/write_string_comparison.bench.cpp
new file mode 100644
index 0000000000000..bbd49f785d60d
--- /dev/null
+++ b/libcxx/test/benchmarks/format/write_string_comparison.bench.cpp
@@ -0,0 +1,221 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include <array>
+#include <concepts>
+#include <cstdio>
+#include <deque>
+#include <format>
+#include <iterator>
+#include <list>
+#include <string>
+#include <string_view>
+#include <vector>
+
+#include "benchmark/benchmark.h"
+#include "test_macros.h"
+
+const char* c_string_6_characters  = "abcdef";
+const char* c_string_60_characters = "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef";
+const char* c_string_6000_characters =
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"
+    "abcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdefabcdef"; // 100 lines
+
+std::string string_6_characters    = c_string_6_characters;
+std::string string_60_characters   = c_string_60_characters;
+std::string string_6000_characters = c_string_6000_characters;
+
+std::string_view string_view_6_characters    = c_string_6_characters;
+std::string_view string_view_60_characters   = c_string_60_characters;
+std::string_view string_view_6000_characters = c_string_6000_characters;
+
+static void BM_sprintf(benchmark::State& state, const char* value) {
+  std::array<char, 10'000> output;
+  for (auto _ : state)
+    benchmark::DoNotOptimize(sprintf(output.data(), "%s", value));
+}
+
+template <class T>
+static void BM_format(benchmark::State& state, const T& value) {
+  for (auto _ : state)
+    benchmark::DoNotOptimize(std::format("{}", value));
+}
+
+template <class Container, class T>
+static void BM_format_to_back_inserter(benchmark::State& state, const T& value) {
+  for (auto _ : state) {
+    Container c;
+    std::format_to(std::back_inserter(c), "{}", value);
+    benchmark::DoNotOptimize(c);
+  }
+}
+
+template <class T, class F>
+static void BM_format_to_iterator(benchmark::State& state, const T& value, F&& f) {
+  auto output = f();
+  for (auto _ : state) {
+    benchmark::DoNotOptimize(std::format_to(std::begin(output), "{}", value));
+  }
+}
+
+#define FORMAT_BENCHMARKS(name, variable)                                                                              \
+  BENCHMARK_CAPTURE(BM_format, name, variable);                                                                        \
+                                                                                                                       \
+  BENCHMARK_TEMPLATE1_CAPTURE(BM_format_to_back_inserter, std::string, name, variable);                                \
+  BENCHMARK_TEMPLATE1_CAPTURE(BM_format_to_back_inserter, std::vector<char>, name, variable);                          \
+  BENCHMARK_TEMPLATE1_CAPTURE(BM_format_to_back_inserter, std::deque<char>, name, variable);                           \
+  BENCHMARK_TEMPLATE1_CAPTURE(BM_format_to_back_inserter, std::list<char>, name, variable);                            \
+                                                                                                                       \
+  BENCHMARK_CAPTURE(BM_format_to_iterator, <std::array> name, variable, ([] {                                          \
+                      std::array<char, 10'000> a;                                                                      \
+                      return a;                                                                                        \
+                    }));                                                                                               \
+  BENCHMARK_CAPTURE(BM_format_to_iterator, <std::string> name, variable, ([] {                                         \
+                      std::string s;                                                                                   \
+                      s.resize(10'000);                                                                                \
+                      return s;                                                                                        \
+                    }));                                                                                               \
+  BENCHMARK_CAPTURE(BM_format_to_iterator, <std::vector> name, variable, ([] {                                         \
+                      std::vector<char> v;                                                                             \
+                      v.resize(10'000);                                                                                \
+                      return v;                                                                                        \
+                    }));                                                                                               \
+  BENCHMARK_CAPTURE(BM_format_to_iterator, <std::deque> name, variable, ([] {                                          \
+                      std::deque<char> d;                                                                              \
+                      d.resize(10'000);                                                                                \
+                      return d;                                                                                        \
+                    }));                                                                                               \
+                                                                                                                       \
+  /* */
+
+// Verify these types have an iterator that format has optimizations for.
+LIBCPP_STATIC_ASSERT(std::same_as<std::array<char, 1>::iterator, char*> || // the type depends on an ABI flag
+                     std::same_as<std::array<char, 1>::iterator, std::__wrap_iter<char*>>);
+LIBCPP_STATIC_ASSERT(std::same_as<std::string::iterator, std::__wrap_iter<char*>>);
+LIBCPP_STATIC_ASSERT(std::same_as<std::vector<char>::iterator, std::__wrap_iter<char*>>);
+
+// Verify these types have an iterator that format does not optimize for
+LIBCPP_STATIC_ASSERT(!std::same_as<std::deque<char>::iterator, char*> &&
+                     !std::same_as<std::deque<char>::iterator, std::__wrap_iter<char*>>);
+LIBCPP_STATIC_ASSERT(!std::same_as<std::list<char>::iterator, char*> &&
+                     !std::same_as<std::list<char>::iterator, std::__wrap_iter<char*>>);
+
+BENCHMARK_CAPTURE(BM_sprintf, C_string_len_6, c_string_6_characters);
+FORMAT_BENCHMARKS(C_string_len_6, c_string_6_characters)
+FORMAT_BENCHMARKS(string_len_6, string_6_characters)
+FORMAT_BENCHMARKS(string_view_len_6, string_view_6_characters)
+
+BENCHMARK_CAPTURE(BM_sprintf, C_string_len_60, c_string_60_characters);
+FORMAT_BENCHMARKS(C_string_len_60, c_string_60_characters)
+FORMAT_BENCHMARKS(string_len_60, string_60_characters)
+FORMAT_BENCHMARKS(string_view_len_60, string_view_60_characters)
+
+BENCHMARK_CAPTURE(BM_sprintf, C_string_len_6000, c_string_6000_characters);
+FORMAT_BENCHMARKS(C_string_len_6000, c_string_6000_characters)
+FORMAT_BENCHMARKS(string_len_6000, string_6000_characters)
+FORMAT_BENCHMARKS(string_view_len_6000, string_view_6000_characters)
+
+BENCHMARK_MAIN();