75 lines
2.0 KiB
C
75 lines
2.0 KiB
C
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// https://github.com/WojciechMula/toys/blob/master/000helpers/linux-perf-events.h
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#pragma once
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#ifdef __linux__
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#include <unistd.h> // for syscall
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#include <sys/ioctl.h> // for ioctl
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#include <asm/unistd.h> // for __NR_perf_event_open
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#include <linux/perf_event.h> // for perf event constants
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#include <cerrno> // for errno
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#include <cstring> // for memset
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#include <stdexcept>
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template <int TYPE = PERF_TYPE_HARDWARE>
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class LinuxEvents {
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int fd;
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perf_event_attr attribs;
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public:
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LinuxEvents(int config) : fd(0) {
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memset(&attribs, 0, sizeof(attribs));
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attribs.type = TYPE;
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attribs.size = sizeof(attribs);
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attribs.config = config;
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attribs.disabled = 1;
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attribs.exclude_kernel = 1;
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attribs.exclude_hv = 1;
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const int pid = 0; // the current process
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const int cpu = -1; // all CPUs
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const int group = -1; // no group
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const unsigned long flags = 0;
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fd = syscall(__NR_perf_event_open, &attribs, pid, cpu, group, flags);
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if (fd == -1) {
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report_error("perf_event_open");
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}
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}
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~LinuxEvents() {
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close(fd);
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}
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void start() {
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if (ioctl(fd, PERF_EVENT_IOC_RESET, 0) == -1) {
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report_error("ioctl(PERF_EVENT_IOC_RESET)");
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}
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if (ioctl(fd, PERF_EVENT_IOC_ENABLE, 0) == -1) {
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report_error("ioctl(PERF_EVENT_IOC_ENABLE)");
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}
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}
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unsigned long end() {
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if (ioctl(fd, PERF_EVENT_IOC_DISABLE, 0) == -1) {
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report_error("ioctl(PERF_EVENT_IOC_DISABLE)");
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}
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unsigned long result;
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if (read(fd, &result, sizeof(result)) == -1) {
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report_error("read");
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}
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return result;
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}
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private:
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void report_error(const std::string& context) {
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throw std::runtime_error(context + ": " + std::string(strerror(errno)));
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}
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};
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#endif
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