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#include <fcntl.h>
#include <linux/fs.h>
#include <sys/stat.h>
#include <sys/swap.h>
#include <sys/types.h>
#include <unistd.h>
#include <chrono>
#include <iostream>
#include <numeric>
#include <vector>
using namespace std;
static const size_t kPageSize = sysconf(_SC_PAGESIZE);
static constexpr char kZramBlkdevPath[] = "/dev/block/zram0";
static constexpr size_t kPatternSize = 4;
static constexpr size_t kSectorSize = 512;
void fillPageRand(uint32_t *page) {
uint32_t start = rand();
for (int i = 0; i < kPageSize / sizeof(start); i++) {
page[i] = start+i;
}
}
void fillPageCompressible(void* page) {
uint32_t val = rand() & 0xfff;
auto page_ptr = reinterpret_cast<typeof(val)*>(page);
std::vector<typeof(val)> pattern(kPatternSize, 0);
for (auto i = 0u; i < kPatternSize; i++) {
pattern[i] = val + i;
}
// fill in ABCD... pattern
for (int i = 0; i < kPageSize / sizeof(val); i += kPatternSize) {
std::copy_n(pattern.data(), kPatternSize, (page_ptr + i));
}
}
class AlignedAlloc {
void *m_ptr;
public:
AlignedAlloc(size_t size, size_t align) {
posix_memalign(&m_ptr, align, size);
}
~AlignedAlloc() {
free(m_ptr);
}
void *ptr() {
return m_ptr;
}
};
class BlockFd {
int m_fd = -1;
public:
BlockFd(const char *path, bool direct) {
m_fd = open(path, O_RDWR | (direct ? O_DIRECT : 0));
}
size_t getSize() {
size_t blockSize = 0;
int result = ioctl(m_fd, BLKGETSIZE, &blockSize);
if (result < 0) {
cout << "ioctl block size failed" << endl;
}
return blockSize * kSectorSize;
}
~BlockFd() {
if (m_fd >= 0) {
close(m_fd);
}
}
void fillWithCompressible() {
size_t devSize = getSize();
AlignedAlloc page(kPageSize, kPageSize);
for (uint64_t offset = 0; offset < devSize; offset += kPageSize) {
fillPageCompressible((uint32_t*)page.ptr());
ssize_t ret = write(m_fd, page.ptr(), kPageSize);
if (ret != kPageSize) {
cout << "write() failed" << endl;
}
}
}
void benchSequentialRead() {
chrono::time_point<chrono::high_resolution_clock> start, end;
size_t devSize = getSize();
size_t passes = 4;
AlignedAlloc page(kPageSize, kPageSize);
start = chrono::high_resolution_clock::now();
for (int i = 0; i < passes; i++) {
for (uint64_t offset = 0; offset < devSize; offset += kPageSize) {
if (offset == 0)
lseek(m_fd, offset, SEEK_SET);
ssize_t ret = read(m_fd, page.ptr(), kPageSize);
if (ret != kPageSize) {
cout << "read() failed" << endl;
}
}
}
end = chrono::high_resolution_clock::now();
size_t duration = chrono::duration_cast<chrono::microseconds>(end - start).count();
cout << "read: " << (double)devSize * passes / 1024.0 / 1024.0 / (duration / 1000.0 / 1000.0) << "MB/s" << endl;
}
void benchSequentialWrite() {
chrono::time_point<chrono::high_resolution_clock> start, end;
size_t devSize = getSize();
size_t passes = 4;
AlignedAlloc page(kPageSize, kPageSize);
start = chrono::high_resolution_clock::now();
for (int i = 0; i < passes; i++) {
for (uint64_t offset = 0; offset < devSize; offset += kPageSize) {
fillPageCompressible((uint32_t*)page.ptr());
if (offset == 0)
lseek(m_fd, offset, SEEK_SET);
ssize_t ret = write(m_fd, page.ptr(), kPageSize);
if (ret != kPageSize) {
cout << "write() failed" << endl;
}
}
}
end = chrono::high_resolution_clock::now();
size_t duration = chrono::duration_cast<chrono::microseconds>(end - start).count();
cout << "write: " << (double)devSize * passes / 1024.0 / 1024.0 / (duration / 1000.0 / 1000.0) << "MB/s" << endl;
}
};
int bench(bool direct)
{
BlockFd zramDev{kZramBlkdevPath, direct};
zramDev.fillWithCompressible();
zramDev.benchSequentialRead();
zramDev.benchSequentialWrite();
return 0;
}
int main(int argc, char *argv[])
{
int result = swapoff(kZramBlkdevPath);
if (result < 0) {
cout << "swapoff failed: " << strerror(errno) << endl;
}
bench(1);
result = system((string("mkswap ") + string(kZramBlkdevPath)).c_str());
if (result < 0) {
cout << "mkswap failed: " << strerror(errno) << endl;
return -1;
}
result = swapon(kZramBlkdevPath, 0);
if (result < 0) {
cout << "swapon failed: " << strerror(errno) << endl;
return -1;
}
return 0;
}
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