Update benchmark library (nw)

3rdparty/benchmark/CMakeLists.txt

@@ -1,6 +1,14 @@
 cmake_minimum_required (VERSION 2.8.11)
 project (benchmark)
 
+foreach(p
+    CMP0054 # CMake 3.1
+    )
+  if(POLICY ${p})
+    cmake_policy(SET ${p} NEW)
+  endif()
+endforeach()
+
 option(BENCHMARK_ENABLE_TESTING "Enable testing of the benchmark library." ON)
 option(BENCHMARK_ENABLE_LTO "Enable link time optimisation of the benchmark library." OFF)
 # Make sure we can import out CMake functions
@@ -23,73 +31,83 @@ include(CheckCXXCompilerFlag)
 include(AddCXXCompilerFlag)
 include(CXXFeatureCheck)
 
-# Try and enable C++11. Don't use C++14 because it doesn't work in some
-# configurations.
-add_cxx_compiler_flag(-std=c++11)
-if (NOT HAVE_CXX_FLAG_STD_CXX11)
-  add_cxx_compiler_flag(-std=c++0x)
-endif()
-
-# Turn compiler warnings up to 11
 if ("${CMAKE_CXX_COMPILER_ID}" STREQUAL "MSVC")
+  # Turn compiler warnings up to 11
   add_cxx_compiler_flag(-W4)
   add_definitions(-D_CRT_SECURE_NO_WARNINGS)
-else()
-  add_cxx_compiler_flag(-Wall)
-endif()
-add_cxx_compiler_flag(-Wextra)
-add_cxx_compiler_flag(-Wshadow)
-add_cxx_compiler_flag(-Werror RELEASE)
-add_cxx_compiler_flag(-pedantic)
-add_cxx_compiler_flag(-pedantic-errors)
-add_cxx_compiler_flag(-Wshorten-64-to-32)
-add_cxx_compiler_flag(-Wfloat-equal)
-add_cxx_compiler_flag(-Wzero-as-null-pointer-constant)
-add_cxx_compiler_flag(-fstrict-aliasing)
-if (HAVE_CXX_FLAG_FSTRICT_ALIASING)
-  add_cxx_compiler_flag(-Wstrict-aliasing)
-endif()
-add_cxx_compiler_flag(-Wthread-safety)
-if (HAVE_WTHREAD_SAFETY)
-  add_definitions(-DHAVE_WTHREAD_SAFETY)
-  cxx_feature_check(THREAD_SAFETY_ATTRIBUTES)
-endif()
 
-# Link time optimisation
-if (BENCHMARK_ENABLE_LTO)
-  add_cxx_compiler_flag(-flto)
-  if ("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU")
-    find_program(GCC_AR gcc-ar)
-    if (GCC_AR)
-      set(CMAKE_AR ${GCC_AR})
-    endif()
-    find_program(GCC_RANLIB gcc-ranlib)
-    if (GCC_RANLIB)
-      set(CMAKE_RANLIB ${GCC_RANLIB})
+  # Link time optimisation
+  if (BENCHMARK_ENABLE_LTO)
+    set(CMAKE_CXX_FLAGS_RELEASE "/GL")
+    set(CMAKE_STATIC_LINKER_FLAGS_RELEASE "/LTCG")
+    set(CMAKE_SHARED_LINKER_FLAGS_RELEASE "/LTCG")
+    set(CMAKE_EXE_LINKER_FLAGS_RELEASE "/LTCG")
+  endif()
+else()
+  # Try and enable C++11. Don't use C++14 because it doesn't work in some
+  # configurations.
+  add_cxx_compiler_flag(-std=c++11)
+  if (NOT HAVE_CXX_FLAG_STD_CXX11)
+    add_cxx_compiler_flag(-std=c++0x)
+  endif()
+
+  # Turn compiler warnings up to 11
+  add_cxx_compiler_flag(-Wall)
+
+  add_cxx_compiler_flag(-Wextra)
+  add_cxx_compiler_flag(-Wshadow)
+  add_cxx_compiler_flag(-Werror RELEASE)
+  add_cxx_compiler_flag(-pedantic)
+  add_cxx_compiler_flag(-pedantic-errors)
+  add_cxx_compiler_flag(-Wshorten-64-to-32)
+  add_cxx_compiler_flag(-Wfloat-equal)
+  add_cxx_compiler_flag(-Wzero-as-null-pointer-constant)
+  add_cxx_compiler_flag(-fstrict-aliasing)
+  if (HAVE_CXX_FLAG_FSTRICT_ALIASING)
+    add_cxx_compiler_flag(-Wstrict-aliasing)
+  endif()
+  add_cxx_compiler_flag(-Wthread-safety)
+  if (HAVE_WTHREAD_SAFETY)
+    add_definitions(-DHAVE_WTHREAD_SAFETY)
+    cxx_feature_check(THREAD_SAFETY_ATTRIBUTES)
+  endif()
+
+  # Link time optimisation
+  if (BENCHMARK_ENABLE_LTO)
+    add_cxx_compiler_flag(-flto)
+    if ("${CMAKE_C_COMPILER_ID}" STREQUAL "GNU")
+      find_program(GCC_AR gcc-ar)
+      if (GCC_AR)
+        set(CMAKE_AR ${GCC_AR})
+      endif()
+      find_program(GCC_RANLIB gcc-ranlib)
+      if (GCC_RANLIB)
+        set(CMAKE_RANLIB ${GCC_RANLIB})
+      endif()
     endif()
   endif()
-endif()
 
-# Coverage build type
-set(CMAKE_CXX_FLAGS_COVERAGE "${CMAKE_CXX_FLAGS_DEBUG}" CACHE STRING
-  "Flags used by the C++ compiler during coverage builds."
-  FORCE)
-set(CMAKE_EXE_LINKER_FLAGS_COVERAGE
-  "${CMAKE_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING
-  "Flags used for linking binaries during coverage builds."
-  FORCE)
-set(CMAKE_SHARED_LINKER_FLAGS_COVERAGE
-  "${CMAKE_SHARED_LINKER_FLAGS_DEBUG}" CACHE STRING
-  "Flags used by the shared libraries linker during coverage builds."
-  FORCE)
-mark_as_advanced(
-  CMAKE_CXX_FLAGS_COVERAGE
-  CMAKE_EXE_LINKER_FLAGS_COVERAGE
-  CMAKE_SHARED_LINKER_FLAGS_COVERAGE)
-set(CMAKE_BUILD_TYPE "${CMAKE_BUILD_TYPE}" CACHE STRING
-  "Choose the type of build, options are: None Debug Release RelWithDebInfo MinSizeRel Coverage."
-  FORCE)
-add_cxx_compiler_flag(--coverage COVERAGE)
+  # Coverage build type
+  set(CMAKE_CXX_FLAGS_COVERAGE "${CMAKE_CXX_FLAGS_DEBUG}" CACHE STRING
+    "Flags used by the C++ compiler during coverage builds."
+    FORCE)
+  set(CMAKE_EXE_LINKER_FLAGS_COVERAGE
+    "${CMAKE_EXE_LINKER_FLAGS_DEBUG}" CACHE STRING
+    "Flags used for linking binaries during coverage builds."
+    FORCE)
+  set(CMAKE_SHARED_LINKER_FLAGS_COVERAGE
+    "${CMAKE_SHARED_LINKER_FLAGS_DEBUG}" CACHE STRING
+    "Flags used by the shared libraries linker during coverage builds."
+    FORCE)
+  mark_as_advanced(
+    CMAKE_CXX_FLAGS_COVERAGE
+    CMAKE_EXE_LINKER_FLAGS_COVERAGE
+    CMAKE_SHARED_LINKER_FLAGS_COVERAGE)
+  set(CMAKE_BUILD_TYPE "${CMAKE_BUILD_TYPE}" CACHE STRING
+    "Choose the type of build, options are: None Debug Release RelWithDebInfo MinSizeRel Coverage."
+    FORCE)
+  add_cxx_compiler_flag(--coverage COVERAGE)
+endif()
 
 # C++ feature checks
 cxx_feature_check(STD_REGEX)

3rdparty/benchmark/README.md

@@ -243,7 +243,7 @@ The `context` attribute contains information about the run in general, including
 information about the CPU and the date.
 The `benchmarks` attribute contains a list of ever benchmark run. Example json
 output looks like:
-```
+``` json
 {
   "context": {
     "date": "2015/03/17-18:40:25",
@@ -290,6 +290,20 @@ name,iterations,real_time,cpu_time,bytes_per_second,items_per_second,label
 "BM_SetInsert/1024/10",106365,17238.4,8421.53,4.74973e+06,1.18743e+06,
 ```
 
+Debug vs Release
+----------------
+By default, benchmark builds as a debug library. You will see a warning in the output when this is the case. To build it as a release library instead, use:
+
+```
+cmake -DCMAKE_BUILD_TYPE=Release
+```
+
+To enable link-time optimisation, use
+
+```
+cmake -DCMAKE_BUILD_TYPE=Release -DBENCHMARK_ENABLE_LTO=true
+```
+
 Linking against the library
 ---------------------------
 When using gcc, it is necessary to link against pthread to avoid runtime exceptions. This is due to how gcc implements std::thread. See [issue #67](https://github.com/google/benchmark/issues/67) for more details.

3rdparty/benchmark/appveyor.yml

@@ -12,9 +12,16 @@ platform:
 
 environment:
   matrix:
+    - compiler: msvc-12-seh
+    - compiler: msvc-14-seh
     - compiler: gcc-4.9.2-posix
 #    - compiler: gcc-4.8.4-posix
-#    - compiler: msvc-12-seh
+
+artifacts:
+  - path: '_build/CMakeFiles/*.log'
+    name: logs
+  - path: '_build/Testing/**/*.xml'
+    name: test_results
 
 install:
   # derive some extra information
@@ -35,18 +42,83 @@ before_build:
   - if "%compiler_name%"=="gcc" (set "build=mingw32-make -j4")
   - if "%compiler_name%"=="gcc" (set "test=mingw32-make CTEST_OUTPUT_ON_FAILURE=1 test")
   # msvc specific commands
-  # TODO :)
+  - if "%compiler_name%"=="msvc" if "%compiler_version%"=="12" if "%platform%"=="x86" (set "generator=Visual Studio 12 2013")
+  - if "%compiler_name%"=="msvc" if "%compiler_version%"=="12" if "%platform%"=="x64" (set "generator=Visual Studio 12 2013 Win64")
+  - if "%compiler_name%"=="msvc" if "%compiler_version%"=="14" if "%platform%"=="x86" (set "generator=Visual Studio 14 2015")
+  - if "%compiler_name%"=="msvc" if "%compiler_version%"=="14" if "%platform%"=="x64" (set "generator=Visual Studio 14 2015 Win64")
+  - if "%compiler_name%"=="msvc" (set "build=cmake --build . --config %variant%")
+  - if "%compiler_name%"=="msvc" (set "test=ctest -c Release -D CTEST_OUTPUT_ON_FAILURE:STRING=1")
   # add the compiler path if needed
   - if not "%compiler_path%"=="" (set "PATH=%PATH%;%compiler_path%")
   # git bash conflicts with MinGW makefiles
-  - if "%generator%"=="MinGW Makefiles" (set "PATH=%PATH:C:\Program Files (x86)\Git\bin=%")
+  - if "%generator%"=="MinGW Makefiles" (set "PATH=%PATH:C:\Program Files\Git\usr\bin;=%")
 
 build_script:
-  - cmake -G "%generator%" "-DCMAKE_BUILD_TYPE=%variant%" "-DBUILD_SHARED_LIBS=%shared%"
-  - cmd /c "%build%"
+- ps: |
+    md _build -Force
+    cd _build
+    & cmake -G "$env:generator" "-DCMAKE_BUILD_TYPE=$env:variant" "-DBUILD_SHARED_LIBS=$env:shared" ..
+    if ($LastExitCode -ne 0) {
+        throw "Exec: $ErrorMessage"
+    }
+    iex "& $env:build"
+    if ($LastExitCode -ne 0) {
+        throw "Exec: $ErrorMessage"
+    }
 
 test_script:
-  - cmd /c "%test%"
+- ps: |
+    iex "& $env:test"
+    if ($LastExitCode -ne 0) {
+        throw "Exec: $ErrorMessage"
+    }
+
+    function Add-CTest-Result($testResult)
+    {
+        $tests = ([xml](get-content $testResult)).Site.Testing
+        $testsCount = 0
+        $anyFailures = $FALSE
+
+        foreach ($test in $tests.test) {
+            $testsCount++
+            $testName = $test.Name
+            $testpath = $test.Path
+            $timeNode = $test.SelectSingleNode('Results/NamedMeasurement[@name="Execution Time"]/Value')
+            if ($test.status -eq "failure") {
+                $time = ([double]$timeNode.InnerText * 1000)
+                Add-AppveyorTest $testName -Outcome Failed -FileName $testpath -Duration $time -ErrorMessage $($test.results.measurement.value)
+                Add-AppveyorMessage `"$testName failed`" -Category Error
+                $anyFailures = $TRUE
+            }
+            elseif ($test.status -eq "skipped") {
+                Add-AppveyorTest $testName -Outcome Ignored -Filename $testpath
+            }
+            else {
+                $time = ([double]$timeNode.InnerText * 1000)
+                Add-AppveyorTest $testName -Outcome Passed -FileName $testpath -Duration $time -StdOut $($test.results.measurement.value)
+            }
+        }
+        return $testsCount, $anyFailures
+    }
+
+    $testsCount = 0
+    $anyFailures = $FALSE
+
+    # Run tests and upload results to AppVeyor one by one
+    Get-ChildItem ".\Testing\*.xml" -Recurse | foreach {
+        $testfile = $_.fullname
+        $count, $testsResult = Add-CTest-Result $testfile
+        Write-Host "Found $testfile with $count tests"
+        $testsCount = $testsCount + $count
+        $anyFailures = $anyFailures -or $testsResult
+    }
+
+    Write-Host "There are $testsCount tests found"
+
+    if ($anyFailures -eq $TRUE){
+        Write-Host "Failing build as there are broken tests"
+        $host.SetShouldExit(1)
+    }
 
 matrix:
   fast_finish: true

3rdparty/benchmark/include/benchmark/benchmark_api.h

@@ -221,7 +221,7 @@ inline BENCHMARK_ALWAYS_INLINE void DoNotOptimize(Tp const& value) {
 // benchmark to use.
 class State {
 public:
-  State(size_t max_iters, bool has_x, int x, bool has_y, int y, int thread_i);
+  State(size_t max_iters, bool has_x, int x, bool has_y, int y, int thread_i, int n_threads);
 
   // Returns true iff the benchmark should continue through another iteration.
   // NOTE: A benchmark may not return from the test until KeepRunning() has
@@ -358,7 +358,10 @@ private:
   size_t items_processed_;
 
 public:
+  // Index of the executing thread. Values from [0, threads).
   const int thread_index;
+  // Number of threads concurrently executing the benchmark.
+  const int threads;
   const size_t max_iterations;
 
 private:
@@ -486,13 +489,13 @@ public:
     Fixture() : internal::Benchmark("") {}
 
     virtual void Run(State& st) {
-      this->SetUp();
+      this->SetUp(st);
       this->BenchmarkCase(st);
-      this->TearDown();
+      this->TearDown(st);
     }
 
-    virtual void SetUp() {}
-    virtual void TearDown() {}
+    virtual void SetUp(const State&) {}
+    virtual void TearDown(const State&) {}
 
 protected:
     virtual void BenchmarkCase(State&) = 0;

3rdparty/benchmark/src/benchmark.cc

@@ -599,7 +599,7 @@ namespace {
 void RunInThread(const benchmark::internal::Benchmark::Instance* b,
                  size_t iters, int thread_id,
                  ThreadStats* total) EXCLUDES(GetBenchmarkLock()) {
-  State st(iters, b->has_arg1, b->arg1, b->has_arg2, b->arg2, thread_id);
+  State st(iters, b->has_arg1, b->arg1, b->has_arg2, b->arg2, thread_id, b->threads);
   b->benchmark->Run(st);
   CHECK(st.iterations() == st.max_iterations) <<
     "Benchmark returned before State::KeepRunning() returned false!";
@@ -736,15 +736,17 @@ void RunBenchmark(const benchmark::internal::Benchmark::Instance& b,
 }  // namespace
 
 State::State(size_t max_iters, bool has_x, int x, bool has_y, int y,
-             int thread_i)
+             int thread_i, int n_threads)
     : started_(false), total_iterations_(0),
       has_range_x_(has_x), range_x_(x),
       has_range_y_(has_y), range_y_(y),
       bytes_processed_(0), items_processed_(0),
       thread_index(thread_i),
+      threads(n_threads),
       max_iterations(max_iters)
 {
     CHECK(max_iterations != 0) << "At least one iteration must be run";
+    CHECK_LT(thread_index, threads) << "thread_index must be less than threads";
 }
 
 void State::PauseTiming() {

3rdparty/benchmark/src/console_reporter.cc

@@ -37,7 +37,7 @@ bool ConsoleReporter::ReportContext(const Context& context) {
 
   if (context.cpu_scaling_enabled) {
     std::cerr << "***WARNING*** CPU scaling is enabled, the benchmark "
-                 "real time measurements may be noisy and will incure extra "
+                 "real time measurements may be noisy and will incur extra "
                  "overhead.\n";
   }
 

3rdparty/benchmark/src/csv_reporter.cc

@@ -34,7 +34,7 @@ bool CSVReporter::ReportContext(const Context& context) {
 
   if (context.cpu_scaling_enabled) {
     std::cerr << "***WARNING*** CPU scaling is enabled, the benchmark "
-                 "real time measurements may be noisy and will incure extra "
+                 "real time measurements may be noisy and will incur extra "
                  "overhead.\n";
   }
 

3rdparty/benchmark/src/cycleclock.h

@@ -99,6 +99,14 @@ inline BENCHMARK_ALWAYS_INLINE int64_t Now() {
   _asm rdtsc
 #elif defined(COMPILER_MSVC)
   return __rdtsc();
+#elif defined(__aarch64__)
+  // System timer of ARMv8 runs at a different frequency than the CPU's.
+  // The frequency is fixed, typically in the range 1-50MHz.  It can be
+  // read at CNTFRQ special register.  We assume the OS has set up
+  // the virtual timer properly.
+  int64_t virtual_timer_value;
+  asm volatile("mrs %0, cntvct_el0" : "=r"(virtual_timer_value));
+  return virtual_timer_value;
 #elif defined(__ARM_ARCH)
 #if (__ARM_ARCH >= 6)  // V6 is the earliest arch that has a standard cyclecount
   uint32_t pmccntr;

3rdparty/benchmark/src/sysinfo.cc

@@ -174,12 +174,16 @@ void InitializeSystemInfo() {
         if (freqstr[1] != '\0' && *err == '\0' && bogo_clock > 0)
           saw_bogo = true;
       }
-    } else if (strncasecmp(line, "processor", sizeof("processor") - 1) == 0) {
+    } else if (strncmp(line, "processor", sizeof("processor") - 1) == 0) {
+      // The above comparison is case-sensitive because ARM kernels often
+      // include a "Processor" line that tells you about the CPU, distinct
+      // from the usual "processor" lines that give you CPU ids. No current
+      // Linux architecture is using "Processor" for CPU ids.
       num_cpus++;  // count up every time we see an "processor :" entry
-      const char* freqstr = strchr(line, ':');
-      if (freqstr) {
-        const long cpu_id = strtol(freqstr + 1, &err, 10);
-        if (freqstr[1] != '\0' && *err == '\0' && max_cpu_id < cpu_id)
+      const char* id_str = strchr(line, ':');
+      if (id_str) {
+        const long cpu_id = strtol(id_str + 1, &err, 10);
+        if (id_str[1] != '\0' && *err == '\0' && max_cpu_id < cpu_id)
           max_cpu_id = cpu_id;
       }
     }
@@ -201,7 +205,7 @@ void InitializeSystemInfo() {
   } else {
     if ((max_cpu_id + 1) != num_cpus) {
       fprintf(stderr,
-              "CPU ID assignments in /proc/cpuinfo seems messed up."
+              "CPU ID assignments in /proc/cpuinfo seem messed up."
               " This is usually caused by a bad BIOS.\n");
     }
     cpuinfo_num_cpus = num_cpus;

3rdparty/benchmark/test/CMakeLists.txt

@@ -39,6 +39,9 @@ add_test(basic_benchmark basic_test --benchmark_min_time=0.01)
 compile_benchmark_test(fixture_test)
 add_test(fixture_test fixture_test --benchmark_min_time=0.01)
 
+compile_benchmark_test(map_test)
+add_test(map_test map_test --benchmark_min_time=0.01)
+
 compile_benchmark_test(cxx03_test)
 set_target_properties(cxx03_test
     PROPERTIES COMPILE_FLAGS "${CXX03_FLAGS}")

3rdparty/benchmark/test/benchmark_test.cc

@@ -150,5 +150,29 @@ static void BM_LongTest(benchmark::State& state) {
 }
 BENCHMARK(BM_LongTest)->Range(1<<16,1<<28);
 
+static void BM_ParallelMemset(benchmark::State& state) {
+  int size = state.range_x() / sizeof(int);
+  int thread_size = size / state.threads;
+  int from = thread_size * state.thread_index;
+  int to = from + thread_size;
+
+  if (state.thread_index == 0) {
+    test_vector = new std::vector<int>(size);
+  }
+
+  while (state.KeepRunning()) {
+    for (int i = from; i < to; i++) {
+      // No need to lock test_vector_mu as ranges
+      // do not overlap between threads.
+      benchmark::DoNotOptimize(test_vector->at(i) = 1);
+    }
+  }
+
+  if (state.thread_index == 0) {
+    delete test_vector;
+  }
+}
+BENCHMARK(BM_ParallelMemset)->Arg(10 << 20)->ThreadRange(1, 4);
+
 BENCHMARK_MAIN()
 

3rdparty/benchmark/test/fixture_test.cc

@@ -2,41 +2,51 @@
 #include "benchmark/benchmark.h"
 
 #include <cassert>
+#include <memory>
 
-class MyFixture : public ::benchmark::Fixture
-{
-public:
-    void SetUp() {
-        data = new int(42);
+class MyFixture : public ::benchmark::Fixture {
+ public:
+  void SetUp(const ::benchmark::State& state) {
+    if (state.thread_index == 0) {
+      assert(data.get() == nullptr);
+      data.reset(new int(42));
     }
+  }
 
-    void TearDown() {
-        assert(data != nullptr);
-        delete data;
-        data = nullptr;
+  void TearDown(const ::benchmark::State& state) {
+    if (state.thread_index == 0) {
+      assert(data.get() != nullptr);
+      data.reset();
     }
+  }
 
-    ~MyFixture() {
-      assert(data == nullptr);
-    }
+  ~MyFixture() {
+    assert(data == nullptr);
+  }
 
-    int* data;
+  std::unique_ptr<int> data;
 };
 
 
 BENCHMARK_F(MyFixture, Foo)(benchmark::State& st) {
-    assert(data != nullptr);
-    assert(*data == 42);
-    while (st.KeepRunning()) {
-    }
+  assert(data.get() != nullptr);
+  assert(*data == 42);
+  while (st.KeepRunning()) {
+  }
 }
 
 BENCHMARK_DEFINE_F(MyFixture, Bar)(benchmark::State& st) {
+  if (st.thread_index == 0) {
+    assert(data.get() != nullptr);
+    assert(*data == 42);
+  }
   while (st.KeepRunning()) {
+    assert(data.get() != nullptr);
+    assert(*data == 42);
   }
   st.SetItemsProcessed(st.range_x());
 }
 BENCHMARK_REGISTER_F(MyFixture, Bar)->Arg(42);
-
+BENCHMARK_REGISTER_F(MyFixture, Bar)->Arg(42)->ThreadPerCpu();
 
 BENCHMARK_MAIN()

3rdparty/benchmark/test/map_test.cc

@@ -0,0 +1,58 @@
+#include "benchmark/benchmark.h"
+
+#include <cstdlib>
+#include <map>
+
+namespace {
+
+std::map<int, int> ConstructRandomMap(int size) {
+  std::map<int, int> m;
+  for (int i = 0; i < size; ++i) {
+    m.insert(std::make_pair(rand() % size, rand() % size));
+  }
+  return m;
+}
+
+}  // namespace
+
+// Basic version.
+static void BM_MapLookup(benchmark::State& state) {
+  const int size = state.range_x();
+  while (state.KeepRunning()) {
+    state.PauseTiming();
+    std::map<int, int> m = ConstructRandomMap(size);
+    state.ResumeTiming();
+    for (int i = 0; i < size; ++i) {
+      benchmark::DoNotOptimize(m.find(rand() % size));
+    }
+  }
+  state.SetItemsProcessed(state.iterations() * size);
+}
+BENCHMARK(BM_MapLookup)->Range(1 << 3, 1 << 12);
+
+// Using fixtures.
+class MapFixture : public ::benchmark::Fixture {
+ public:
+  void SetUp(const ::benchmark::State& st) {
+    m = ConstructRandomMap(st.range_x());
+  }
+
+  void TearDown(const ::benchmark::State&) {
+    m.clear();
+  }
+
+  std::map<int, int> m;
+};
+
+BENCHMARK_DEFINE_F(MapFixture, Lookup)(benchmark::State& state) {
+  const int size = state.range_x();
+  while (state.KeepRunning()) {
+    for (int i = 0; i < size; ++i) {
+      benchmark::DoNotOptimize(m.find(rand() % size));
+    }
+  }
+  state.SetItemsProcessed(state.iterations() * size);
+}
+BENCHMARK_REGISTER_F(MapFixture, Lookup)->Range(1<<3, 1<<12);
+
+BENCHMARK_MAIN()