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// -*- mode:C++; tab-width:8; c-basic-offset:2; indent-tabs-mode:t -*-
// vim: ts=8 sw=2 smarttab
#include "numa.h"
#include <cstring>
#include <errno.h>
#include <iostream>
#include "include/stringify.h"
#include "common/safe_io.h"
using namespace std::literals;
using std::set;
// list
#if defined(__linux__)
int parse_cpu_set_list(const char *s,
size_t *cpu_set_size,
cpu_set_t *cpu_set)
{
CPU_ZERO(cpu_set);
while (*s) {
char *end;
int a = strtol(s, &end, 10);
if (end == s) {
return -EINVAL;
}
if (*end == '-') {
s = end + 1;
int b = strtol(s, &end, 10);
if (end == s) {
return -EINVAL;
}
for (; a <= b; ++a) {
CPU_SET(a, cpu_set);
}
*cpu_set_size = a;
} else {
CPU_SET(a, cpu_set);
*cpu_set_size = a + 1;
}
if (*end == 0) {
break;
}
if (*end != ',') {
return -EINVAL;
}
s = end + 1;
}
return 0;
}
std::string cpu_set_to_str_list(size_t cpu_set_size,
const cpu_set_t *cpu_set)
{
std::string r;
unsigned a = 0;
while (true) {
while (a < cpu_set_size && !CPU_ISSET(a, cpu_set)) {
++a;
}
if (a >= cpu_set_size) {
break;
}
unsigned b = a + 1;
while (b < cpu_set_size && CPU_ISSET(b, cpu_set)) {
++b;
}
if (r.size()) {
r += ",";
}
if (b > a + 1) {
r += stringify(a) + "-" + stringify(b - 1);
} else {
r += stringify(a);
}
a = b;
}
return r;
}
std::set<int> cpu_set_to_set(size_t cpu_set_size,
const cpu_set_t *cpu_set)
{
set<int> r;
unsigned a = 0;
while (true) {
while (a < cpu_set_size && !CPU_ISSET(a, cpu_set)) {
++a;
}
if (a >= cpu_set_size) {
break;
}
unsigned b = a + 1;
while (b < cpu_set_size && CPU_ISSET(b, cpu_set)) {
++b;
}
while (a < b) {
r.insert(a);
++a;
}
}
return r;
}
int get_numa_node_cpu_set(
int node,
size_t *cpu_set_size,
cpu_set_t *cpu_set)
{
std::string fn = "/sys/devices/system/node/node";
fn += stringify(node);
fn += "/cpulist";
int fd = ::open(fn.c_str(), O_RDONLY);
if (fd < 0) {
return -errno;
}
char buf[1024];
int r = safe_read(fd, &buf, sizeof(buf));
if (r < 0) {
goto out;
}
buf[r] = 0;
while (r > 0 && ::isspace(buf[--r])) {
buf[r] = 0;
}
r = parse_cpu_set_list(buf, cpu_set_size, cpu_set);
if (r < 0) {
goto out;
}
r = 0;
out:
::close(fd);
return r;
}
static int easy_readdir(const std::string& dir, std::set<std::string> *out)
{
DIR *h = ::opendir(dir.c_str());
if (!h) {
return -errno;
}
struct dirent *de = nullptr;
while ((de = ::readdir(h))) {
if (strcmp(de->d_name, ".") == 0 ||
strcmp(de->d_name, "..") == 0) {
continue;
}
out->insert(de->d_name);
}
closedir(h);
return 0;
}
#ifdef HAVE_DPDK
static std::string get_task_comm(pid_t tid)
{
static const char* comm_fmt = "/proc/self/task/%d/comm";
char comm_name[strlen(comm_fmt) + 8];
snprintf(comm_name, sizeof(comm_name), comm_fmt, tid);
int fd = open(comm_name, O_CLOEXEC | O_RDONLY);
if (fd == -1) {
return "";
}
// see linux/sched.h
static constexpr int TASK_COMM_LEN = 16;
char name[TASK_COMM_LEN];
ssize_t n = safe_read(fd, name, sizeof(name));
close(fd);
if (n < 0) {
return "";
}
assert(static_cast<size_t>(n) <= sizeof(name));
if (name[n - 1] == '\n') {
name[n - 1] = '\0';
} else {
name[n] = '\0';
}
return name;
}
#endif
int set_cpu_affinity_all_threads(size_t cpu_set_size, cpu_set_t *cpu_set)
{
// first set my affinity
int r = sched_setaffinity(getpid(), cpu_set_size, cpu_set);
if (r < 0) {
return -errno;
}
// make 2 passes here so that we (hopefully) catch racing threads creating
// threads.
for (unsigned pass = 0; pass < 2; ++pass) {
// enumerate all child threads from /proc
std::set<std::string> ls;
std::string path = "/proc/"s + stringify(getpid()) + "/task";
r = easy_readdir(path, &ls);
if (r < 0) {
return r;
}
for (auto& i : ls) {
pid_t tid = atoll(i.c_str());
if (!tid) {
continue; // wtf
}
#ifdef HAVE_DPDK
std::string thread_name = get_task_comm(tid);
static const char *dpdk_worker_name = "lcore-worker";
if (!thread_name.compare(0, strlen(dpdk_worker_name), dpdk_worker_name)) {
// ignore dpdk reactor thread, as it takes case of numa by itself
continue;
}
#endif
r = sched_setaffinity(tid, cpu_set_size, cpu_set);
if (r < 0) {
return -errno;
}
}
}
return 0;
}
#else
int parse_cpu_set_list(const char *s,
size_t *cpu_set_size,
cpu_set_t *cpu_set)
{
return -ENOTSUP;
}
std::string cpu_set_to_str_list(size_t cpu_set_size,
const cpu_set_t *cpu_set)
{
return {};
}
std::set<int> cpu_set_to_set(size_t cpu_set_size,
const cpu_set_t *cpu_set)
{
return {};
}
int get_numa_node_cpu_set(int node,
size_t *cpu_set_size,
cpu_set_t *cpu_set)
{
return -ENOTSUP;
}
int set_cpu_affinity_all_threads(size_t cpu_set_size,
cpu_set_t *cpu_set)
{
return -ENOTSUP;
}
#endif
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