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#include <benchmark/benchmark.h>
#include <string>
#include <cstring>
#include <cstdlib>
#include <cstdio>
#include <iostream>
#include <vector>
#include <tuple>
#include <unistd.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <sys/mman.h>
using namespace std;
static const size_t pageSize = getpagesize();
static size_t fsize = 1024 * (1ull << 20);
static size_t pagesTotal = fsize / pageSize;
class Fd {
int m_fd = -1;
public:
int get() { return m_fd; }
void set(int fd) { m_fd = fd; }
Fd() {}
explicit Fd(int fd) : m_fd{fd} {}
~Fd() {
if (m_fd >= 0)
close(m_fd);
}
};
int dummy = 0;
void fillPageJunk(void *ptr)
{
uint64_t seed = (unsigned long long)rand() | ((unsigned long long)rand() << 32);
uint64_t *target = (uint64_t*)ptr;
for (int i = 0; i < pageSize / sizeof(uint64_t); i++) {
*target = seed ^ (uint64_t)(uintptr_t)target;
seed = (seed << 1) | ((seed >> 63) & 1);
target++;
}
}
class FileMap {
string m_name;
size_t m_size;
void *m_ptr = nullptr;
Fd m_fileFd;
public:
enum Hint {
FILE_MAP_HINT_NONE,
FILE_MAP_HINT_RAND,
FILE_MAP_HINT_LINEAR,
};
FileMap(const string &name, size_t size, Hint hint = FILE_MAP_HINT_NONE) : m_name{name}, m_size{size} {
int fd = open(name.c_str(), O_CREAT | O_RDWR, S_IRWXU);
if (fd < 0) {
cout << "Error: open failed for " << name << ": " << strerror(errno) << endl;
exit(1);
}
m_fileFd.set(fd);
fallocate(m_fileFd.get(), 0, 0, size);
unlink(name.c_str());
m_ptr = mmap(nullptr, size, PROT_READ | PROT_WRITE, MAP_SHARED, m_fileFd.get(), 0);
if ((int)(uintptr_t)m_ptr == -1) {
cout << "Error: mmap failed: " << (int)(uintptr_t)m_ptr << ": " << strerror(errno) << endl;
exit(1);
}
switch (hint) {
case FILE_MAP_HINT_NONE: break;
case FILE_MAP_HINT_RAND:
madvise(m_ptr, m_size, MADV_RANDOM);
break;
case FILE_MAP_HINT_LINEAR:
madvise(m_ptr, m_size, MADV_SEQUENTIAL);
break;
}
for (int i = 0; i < m_size / pageSize; i++) {
uint8_t *targetPtr = (uint8_t*)m_ptr + 4096ull * i;
fillPageJunk(targetPtr);
}
}
void benchRandomRead(unsigned int targetPage) {
uint8_t *targetPtr = (uint8_t*)m_ptr + pageSize * targetPage;
dummy += *targetPtr;
}
void benchRandomWrite(unsigned int targetPage) {
uint8_t *targetPtr = (uint8_t*)m_ptr + pageSize * targetPage;
*targetPtr = dummy;
}
void benchLinearRead(unsigned int j) {
uint8_t *targetPtr = (uint8_t*)m_ptr + pageSize * j;
dummy += *targetPtr;
}
void benchLinearWrite(unsigned int j) {
uint8_t *targetPtr = (uint8_t*)m_ptr + pageSize * j;
*targetPtr = dummy;
}
void dropCache() {
int ret1 = msync(m_ptr, m_size, MS_SYNC | MS_INVALIDATE);
madvise(m_ptr, m_size, MADV_DONTNEED);
(void)ret1;
}
~FileMap() {
if (m_ptr)
munmap(m_ptr, m_size);
}
};
static void benchRandomRead(benchmark::State& state) {
FileMap file{"/data/local/tmp/mmap_test", fsize};
while (state.KeepRunning()) {
unsigned int targetPage = rand() % pagesTotal;
file.benchRandomRead(targetPage);
}
state.SetBytesProcessed(state.iterations() * pageSize);
}
BENCHMARK(benchRandomRead);
static void benchRandomWrite(benchmark::State& state) {
FileMap file{"/data/local/tmp/mmap_test", fsize};
while (state.KeepRunning()) {
unsigned int targetPage = rand() % pagesTotal;
file.benchRandomWrite(targetPage);
}
state.SetBytesProcessed(state.iterations() * pageSize);
}
BENCHMARK(benchRandomWrite);
static void benchLinearRead(benchmark::State& state) {
FileMap file{"/data/local/tmp/mmap_test", fsize};
unsigned int j = 0;
while (state.KeepRunning()) {
file.benchLinearRead(j);
j = (j + 1) % pagesTotal;
}
state.SetBytesProcessed(state.iterations() * pageSize);
}
BENCHMARK(benchLinearRead);
static void benchLinearWrite(benchmark::State& state) {
FileMap file{"/data/local/tmp/mmap_test", fsize};
unsigned int j = 0;
while (state.KeepRunning()) {
file.benchLinearWrite(j);
j = (j + 1) % pagesTotal;
}
state.SetBytesProcessed(state.iterations() * pageSize);
}
BENCHMARK(benchLinearWrite);
BENCHMARK_MAIN();
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