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#pragma once
#ifdef __linux__
#include <asm/unistd.h> // for __NR_perf_event_open
#include <linux/perf_event.h> // for perf event constants
#include <sys/ioctl.h> // for ioctl
#include <unistd.h> // for syscall
#include <cerrno> // for errno
#include <cstring> // for memset
#include <stdexcept>
#include <iostream>
#include <vector>
template <int TYPE = PERF_TYPE_HARDWARE> class LinuxEvents {
int fd;
bool working;
perf_event_attr attribs{};
size_t num_events{};
std::vector<uint64_t> temp_result_vec{};
std::vector<uint64_t> ids{};
public:
explicit LinuxEvents(std::vector<int> config_vec) : fd(0), working(true) {
memset(&attribs, 0, sizeof(attribs));
attribs.type = TYPE;
attribs.size = sizeof(attribs);
attribs.disabled = 1;
attribs.exclude_kernel = 1;
attribs.exclude_hv = 1;
attribs.sample_period = 0;
attribs.read_format = PERF_FORMAT_GROUP | PERF_FORMAT_ID;
const int pid = 0; // the current process
const int cpu = -1; // all CPUs
const unsigned long flags = 0;
int group = -1; // no group
num_events = config_vec.size();
ids.resize(config_vec.size());
uint32_t i = 0;
for (auto config : config_vec) {
attribs.config = config;
int _fd = static_cast<int>(syscall(__NR_perf_event_open, &attribs, pid, cpu, group, flags));
if (_fd == -1) {
report_error("perf_event_open");
}
ioctl(_fd, PERF_EVENT_IOC_ID, &ids[i++]);
if (group == -1) {
group = _fd;
fd = _fd;
}
}
temp_result_vec.resize(num_events * 2 + 1);
}
~LinuxEvents() { if (fd != -1) { close(fd); } }
inline void start() {
if (fd != -1) {
if (ioctl(fd, PERF_EVENT_IOC_RESET, PERF_IOC_FLAG_GROUP) == -1) {
report_error("ioctl(PERF_EVENT_IOC_RESET)");
}
if (ioctl(fd, PERF_EVENT_IOC_ENABLE, PERF_IOC_FLAG_GROUP) == -1) {
report_error("ioctl(PERF_EVENT_IOC_ENABLE)");
}
}
}
inline void end(std::vector<unsigned long long> &results) {
if (fd != -1) {
if (ioctl(fd, PERF_EVENT_IOC_DISABLE, PERF_IOC_FLAG_GROUP) == -1) {
report_error("ioctl(PERF_EVENT_IOC_DISABLE)");
}
if (read(fd, temp_result_vec.data(), temp_result_vec.size() * 8) == -1) {
report_error("read");
}
}
// our actual results are in slots 1,3,5, ... of this structure
for (uint32_t i = 1; i < temp_result_vec.size(); i += 2) {
results[i / 2] = temp_result_vec[i];
}
for (uint32_t i = 2; i < temp_result_vec.size(); i += 2) {
if(ids[i/2-1] != temp_result_vec[i]) {
report_error("event mismatch");
}
}
}
bool is_working() {
return working;
}
private:
void report_error(const std::string &) {
working = false;
}
};
#endif
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