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Virtual Memory Benchmark
#ifdef BENCHMARK_HAS_CXX11
#undef BENCHMARK_HAS_CXX11
#endif
#include <benchmark/benchmark.h>
#include <windows.h>
static constexpr size_t MemorySize = 0x10'000 * 4800; /* 300 MiB */
/* #define MEMSET \ */
/* do { \ */
/* for (int i = 0; i < 4800; ++i) \ */
/* benchmark::DoNotOptimize(*((char *)mem + (i * 0x10'000)) = 1); \ */
/* benchmark::ClobberMemory(); \ */
/* } while (0) */
#define MEMSET \
do { \
benchmark::DoNotOptimize(memset(mem, 0xFD, MemorySize)); \
benchmark::ClobberMemory(); \
} while (0)
static void
BM_VMemMemset(benchmark::State &state)
{
void *mem = VirtualAlloc(
nullptr,
MemorySize,
MEM_RESERVE | MEM_COMMIT,
PAGE_READWRITE);
for (auto _ : state) {
((void)_);
MEMSET;
}
VirtualFree(mem, 0, MEM_RELEASE);
}
static void
BM_VMemAllocFree(benchmark::State &state)
{
for (auto _ : state) {
((void)_);
void *mem = VirtualAlloc(
nullptr,
MemorySize,
MEM_RESERVE | MEM_COMMIT,
PAGE_READWRITE);
/*
* Theoretically, the cost of the allocation will be
* seen on first access of the range. This is going to get ignored
* here.
*/
MEMSET;
VirtualFree(mem, 0, MEM_RELEASE);
}
}
static void
BM_VMemDecommit(benchmark::State &state)
{
void *mem = VirtualAlloc(
nullptr,
MemorySize,
MEM_RESERVE,
PAGE_READWRITE);
for (auto _ : state) {
((void)_);
VirtualAlloc(mem, MemorySize, MEM_COMMIT, PAGE_READWRITE);
MEMSET;
VirtualFree(mem, MemorySize, MEM_DECOMMIT);
}
VirtualFree(mem, 0, MEM_RELEASE);
}
static void
BM_VMemDecommitReset(benchmark::State &state)
{
void *mem = VirtualAlloc(
nullptr,
MemorySize,
MEM_RESERVE | MEM_COMMIT,
PAGE_READWRITE);
VirtualAlloc(mem, MemorySize, MEM_RESET, PAGE_READWRITE);
for (auto _ : state) {
((void)_);
VirtualAlloc(mem, MemorySize, MEM_RESET_UNDO, PAGE_READWRITE);
MEMSET;
VirtualAlloc(mem, MemorySize, MEM_RESET, PAGE_READWRITE);
}
VirtualFree(mem, 0, MEM_RELEASE);
}
static void
BM_VMemDecommitMap(benchmark::State &state)
{
LARGE_INTEGER s;
s.QuadPart = MemorySize;
HANDLE hMapping = CreateFileMappingA(
INVALID_HANDLE_VALUE,
0,
PAGE_READWRITE,
s.HighPart,
s.LowPart,
NULL);
for (auto _ : state) {
((void)_);
void *mem = MapViewOfFileEx(
hMapping,
FILE_MAP_ALL_ACCESS,
0,
0,
MemorySize,
nullptr);
MEMSET;
UnmapViewOfFile(mem);
}
CloseHandle(hMapping);
}
BENCHMARK(BM_VMemMemset);
BENCHMARK(BM_VMemAllocFree);
BENCHMARK(BM_VMemDecommit);
BENCHMARK(BM_VMemDecommitReset);
BENCHMARK(BM_VMemDecommitMap);
int
main(int argc, char** argv)
{
/* Initialize benchmarks */
::benchmark::Initialize(&argc, argv);
if (::benchmark::ReportUnrecognizedArguments(argc, argv))
return 1;
::benchmark::RunSpecifiedBenchmarks();
return 0;
}
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