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scylladb/test/perf/linux-perf-event.cc

91 lines
2.2 KiB
C++

/*
* Copyright (C) 2021-present ScyllaDB
*/
/*
* This file is part of Scylla.
*
* Scylla is free software: you can redistribute it and/or modify
* it under the terms of the GNU Affero General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Scylla is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with Scylla. If not, see <http://www.gnu.org/licenses/>.
*/
#include "linux-perf-event.hh"
#include <linux/perf_event.h>
#include <linux/hw_breakpoint.h>
#include <sys/ioctl.h>
#include <asm/unistd.h>
linux_perf_event::linux_perf_event(const struct ::perf_event_attr& attr, pid_t pid, int cpu, int group_fd, unsigned long flags) {
int ret = syscall(__NR_perf_event_open, &attr, pid, cpu, group_fd, flags);
if (ret != -1) {
_fd = ret; // ignore failures, can happen in constrained environments such as containers
}
}
linux_perf_event::~linux_perf_event() {
if (_fd != -1) {
::close(_fd);
}
}
linux_perf_event&
linux_perf_event::operator=(linux_perf_event&& x) noexcept {
if (this != &x) {
if (_fd != -1) {
::close(_fd);
}
_fd = std::exchange(x._fd, -1);
}
return *this;
}
uint64_t
linux_perf_event::read() {
if (_fd == -1) {
return 0;
}
uint64_t ret;
::read(_fd, &ret, sizeof(ret));
return ret;
}
void
linux_perf_event::enable() {
if (_fd == -1) {
return;
}
::ioctl(_fd, PERF_EVENT_IOC_ENABLE, 0);
}
void
linux_perf_event::disable() {
if (_fd == -1) {
return;
}
::ioctl(_fd, PERF_EVENT_IOC_DISABLE, 0);
}
linux_perf_event
linux_perf_event::user_instructions_retired() {
return linux_perf_event(perf_event_attr{
.type = PERF_TYPE_HARDWARE,
.size = sizeof(struct perf_event_attr),
.config = PERF_COUNT_HW_INSTRUCTIONS,
.disabled = 1,
.exclude_kernel = 1,
.exclude_hv = 1,
}, 0, -1, -1, 0);
}