// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (c) 2016 Facebook
*/
#define _GNU_SOURCE
#include <linux/types.h>
#include <stdio.h>
#include <unistd.h>
#include <linux/bpf.h>
#include <errno.h>
#include <string.h>
#include <assert.h>
#include <sched.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <stdlib.h>
#include <time.h>
#include <bpf/bpf.h>
#include "bpf_util.h"
#define min(a, b) ((a) < (b) ? (a) : (b))
#ifndef offsetof
# define offsetof(TYPE, MEMBER) ((size_t)&((TYPE *)0)->MEMBER)
#endif
#define container_of(ptr, type, member) ({ \
const typeof( ((type *)0)->member ) *__mptr = (ptr); \
(type *)( (char *)__mptr - offsetof(type,member) );})
static int nr_cpus;
static unsigned long long *dist_keys;
static unsigned int dist_key_counts;
struct list_head {
struct list_head *next, *prev;
};
static inline void INIT_LIST_HEAD(struct list_head *list)
{
list->next = list;
list->prev = list;
}
static inline void __list_add(struct list_head *new,
struct list_head *prev,
struct list_head *next)
{
next->prev = new;
new->next = next;
new->prev = prev;
prev->next = new;
}
static inline void list_add(struct list_head *new, struct list_head *head)
{
__list_add(new, head, head->next);
}
static inline void __list_del(struct list_head *prev, struct list_head *next)
{
next->prev = prev;
prev->next = next;
}
static inline void __list_del_entry(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
}
static inline void list_move(struct list_head *list, struct list_head *head)
{
__list_del_entry(list);
list_add(list, head);
}
#define list_entry(ptr, type, member) \
container_of(ptr, type, member)
#define list_last_entry(ptr, type, member) \
list_entry((ptr)->prev, type, member)
struct pfect_lru_node {
struct list_head list;
unsigned long long key;
};
struct pfect_lru {
struct list_head list;
struct pfect_lru_node *free_nodes;
unsigned int cur_size;
unsigned int lru_size;
unsigned int nr_unique;
unsigned int nr_misses;
unsigned int total;
int map_fd;
};
static void pfect_lru_init(struct pfect_lru *lru, unsigned int lru_size,
unsigned int nr_possible_elems)
{
lru->map_fd = bpf_map_create(BPF_MAP_TYPE_HASH, NULL,
sizeof(unsigned long long),
sizeof(struct pfect_lru_node *),
nr_possible_elems, NULL);
assert(lru->map_fd != -1);
lru->free_nodes = malloc(lru_size * sizeof(struct pfect_lru_node));
assert(lru->free_nodes);
INIT_LIST_HEAD(&lru->list);
lru->cur_size = 0;
lru->lru_size = lru_size;
lru->nr_unique = lru->nr_misses = lru->total = 0;
}
static void pfect_lru_destroy(struct pfect_lru *lru)
{
close(lru->map_fd);
free(lru->free_nodes);
}
static int pfect_lru_lookup_or_insert(struct pfect_lru *lru,
unsigned long long key)
{
struct pfect_lru_node *node = NULL;
int seen = 0;
lru->total++;
if (!bpf_map_lookup_elem(lru->map_fd, &key, &node)) {
if (node) {
list_move(&node->list, &lru->list);
return 1;
}
seen = 1;
}
if (lru->cur_size < lru->lru_size) {
node = &lru->free_nodes[lru->cur_size++];
INIT_LIST_HEAD(&node->list);
} else {
struct pfect_lru_node *null_node = NULL;
node = list_last_entry(&lru->list,
struct pfect_lru_node,
list);
bpf_map_update_elem(lru->map_fd, &node->key, &null_node, BPF_EXIST);
}
node->key = key;
list_move(&node->list, &lru->list);
lru->nr_misses++;
if (seen) {
assert(!bpf_map_update_elem(lru->map_fd, &key, &node, BPF_EXIST));
} else {
lru->nr_unique++;
assert(!bpf_map_update_elem(lru->map_fd, &key, &node, BPF_NOEXIST));
}
return seen;
}
static unsigned int read_keys(const char *dist_file,
unsigned long long **keys)
{
struct stat fst;
unsigned long long *retkeys;
unsigned int counts = 0;
int dist_fd;
char *b, *l;
int i;
dist_fd = open(dist_file, 0);
assert(dist_fd != -1);
assert(fstat(dist_fd, &fst) == 0);
b = malloc(fst.st_size);
assert(b);
assert(read(dist_fd, b, fst.st_size) == fst.st_size);
close(dist_fd);
for (i = 0; i < fst.st_size; i++) {
if (b[i] == '\n')
counts++;
}
counts++; /* in case the last line has no \n */
retkeys = malloc(counts * sizeof(unsigned long long));
assert(retkeys);
counts = 0;
for (l = strtok(b, "\n"); l; l = strtok(NULL, "\n"))
retkeys[counts++] = strtoull(l, NULL, 10);
free(b);
*keys = retkeys;
return counts;
}
static int create_map(int map_type, int map_flags, unsigned int size)
{
LIBBPF_OPTS(bpf_map_create_opts, opts,
.map_flags = map_flags,
);
int map_fd;
map_fd = bpf_map_create(map_type, NULL, sizeof(unsigned long long),
sizeof(unsigned long long), size, &opts);
if (map_fd == -1)
perror("bpf_create_map");
return map_fd;
}
static int sched_next_online(int pid, int next_to_try)
{
cpu_set_t cpuset;
if (next_to_try == nr_cpus)
return -1;
while (next_to_try < nr_cpus) {
CPU_ZERO(&cpuset);
CPU_SET(next_to_try++, &cpuset);
if (!sched_setaffinity(pid, sizeof(cpuset), &cpuset))
break;
}
return next_to_try;
}
static void run_parallel(unsigned int tasks, void (*fn)(int i, void *data),
void *data)
{
int next_sched_cpu = 0;
pid_t pid[tasks];
int i;
for (i = 0; i < tasks; i++) {
pid[i] = fork();
if (pid[i] == 0) {
next_sched_cpu = sched_next_online(0, next_sched_cpu);
fn(i, data);
exit(0);
} else if (pid[i] == -1) {
printf("couldn't spawn #%d process\n", i);
exit(1);
}
/* It is mostly redundant and just allow the parent
* process to update next_shced_cpu for the next child
* process
*/
next_sched_cpu = sched_next_online(pid[i], next_sched_cpu);
}
for (i = 0; i < tasks; i++) {
int status;
assert(waitpid(pid[i], &status, 0) == pid[i]);
assert(status == 0);
}
}
static void do_test_lru_dist(int task, void *data)
{
unsigned int nr_misses = 0;
struct pfect_lru pfect_lru;
unsigned long long key, value = 1234;
unsigned int i;
unsigned int lru_map_fd = ((unsigned int *)data)[0];
unsigned int lru_size = ((unsigned int *)data)[1];
unsigned long long key_offset = task * dist_key_counts;
pfect_lru_init(&pfect_lru, lru_size, dist_key_counts);
for (i = 0; i < dist_key_counts; i++) {
key = dist_keys[i] + key_offset;
pfect_lru_lookup_or_insert(&pfect_lru, key);
if (!bpf_map_lookup_elem(lru_map_fd, &key, &value))
continue;
if (bpf_map_update_elem(lru_map_fd, &key, &value, BPF_NOEXIST)) {
printf("bpf_map_update_elem(lru_map_fd, %llu): errno:%d\n",
key, errno);
assert(0);
}
nr_misses++;
}
printf(" task:%d BPF LRU: nr_unique:%u(/%u) nr_misses:%u(/%u)\n",
task, pfect_lru.nr_unique, dist_key_counts, nr_misses,
dist_key_counts);
printf(" task:%d Perfect LRU: nr_unique:%u(/%u) nr_misses:%u(/%u)\n",
task, pfect_lru.nr_unique, pfect_lru.total,
pfect_lru.nr_misses, pfect_lru.total);
pfect_lru_destroy(&pfect_lru);
close(lru_map_fd);
}
static void test_parallel_lru_dist(int map_type, int map_flags,
int nr_tasks, unsigned int lru_size)
{
int child_data[2];
int lru_map_fd;
printf("%s (map_type:%d map_flags:0x%X):\n", __func__, map_type,
map_flags);
if (map_flags & BPF_F_NO_COMMON_LRU)
lru_map_fd = create_map(map_type, map_flags,
nr_cpus * lru_size);
else
lru_map_fd = create_map(map_type, map_flags,
nr_tasks * lru_size);
assert(lru_map_fd != -1);
child_data[0] = lru_map_fd;
child_data[1] = lru_size;
run_parallel(nr_tasks, do_test_lru_dist, child_data);
close(lru_map_fd);
}
static void test_lru_loss0(int map_type, int map_flags)
{
unsigned long long key, value[nr_cpus];
unsigned int old_unused_losses = 0;
unsigned int new_unused_losses = 0;
unsigned int used_losses = 0;
int map_fd;
printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type,
map_flags);
assert(sched_next_online(0, 0) != -1);
if (map_flags & BPF_F_NO_COMMON_LRU)
map_fd = create_map(map_type, map_flags, 900 * nr_cpus);
else
map_fd = create_map(map_type, map_flags, 900);
assert(map_fd != -1);
value[0] = 1234;
for (key = 1; key <= 1000; key++) {
int start_key, end_key;
assert(bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST) == 0);
start_key = 101;
end_key = min(key, 900);
while (start_key <= end_key) {
bpf_map_lookup_elem(map_fd, &start_key, value);
start_key++;
}
}
for (key = 1; key <= 1000; key++) {
if (bpf_map_lookup_elem(map_fd, &key, value)) {
if (key <= 100)
old_unused_losses++;
else if (key <= 900)
used_losses++;
else
new_unused_losses++;
}
}
close(map_fd);
printf("older-elem-losses:%d(/100) active-elem-losses:%d(/800) "
"newer-elem-losses:%d(/100)\n",
old_unused_losses, used_losses, new_unused_losses);
}
static void test_lru_loss1(int map_type, int map_flags)
{
unsigned long long key, value[nr_cpus];
int map_fd;
unsigned int nr_losses = 0;
printf("%s (map_type:%d map_flags:0x%X): ", __func__, map_type,
map_flags);
assert(sched_next_online(0, 0) != -1);
if (map_flags & BPF_F_NO_COMMON_LRU)
map_fd = create_map(map_type, map_flags, 1000 * nr_cpus);
else
map_fd = create_map(map_type, map_flags, 1000);
assert(map_fd != -1);
value[0] = 1234;
for (key = 1; key <= 1000; key++)
assert(!bpf_map_update_elem(map_fd, &key, value, BPF_NOEXIST));
for (key = 1; key <= 1000; key++) {
if (bpf_map_lookup_elem(map_fd, &key, value))
nr_losses++;
}
close(map_fd);
printf("nr_losses:%d(/1000)\n", nr_losses);
}
static void do_test_parallel_lru_loss(int task, void *data)
{
const unsigned int nr_stable_elems = 1000;
const unsigned int nr_repeats = 100000;
int map_fd = *(int *)data;
unsigned long long stable_base;
unsigned long long key, value[nr_cpus];
unsigned long long next_ins_key;
unsigned int nr_losses = 0;
unsigned int i;
stable_base = task * nr_repeats * 2 + 1;
next_ins_key = stable_base;
value[0] = 1234;
for (i = 0; i < nr_stable_elems; i++) {
assert(bpf_map_update_elem(map_fd, &next_ins_key, value,
BPF_NOEXIST) == 0);
next_ins_key++;
}
for (i = 0; i < nr_repeats; i++) {
int rn;
rn = rand();
if (rn % 10) {
key = rn % nr_stable_elems + stable_base;
bpf_map_lookup_elem(map_fd, &key, value);
} else {
bpf_map_update_elem(map_fd, &next_ins_key, value,
BPF_NOEXIST);
next_ins_key++;
}
}
key = stable_base;
for (i = 0; i < nr_stable_elems; i++) {
if (bpf_map_lookup_elem(map_fd, &key, value))
nr_losses++;
key++;
}
printf(" task:%d nr_losses:%u\n", task, nr_losses);
}
static void test_parallel_lru_loss(int map_type, int map_flags, int nr_tasks)
{
int map_fd;
printf("%s (map_type:%d map_flags:0x%X):\n", __func__, map_type,
map_flags);
/* Give 20% more than the active working set */
if (map_flags & BPF_F_NO_COMMON_LRU)
map_fd = create_map(map_type, map_flags,
nr_cpus * (1000 + 200));
else
map_fd = create_map(map_type, map_flags,
nr_tasks * (1000 + 200));
assert(map_fd != -1);
run_parallel(nr_tasks, do_test_parallel_lru_loss, &map_fd);
close(map_fd);
}
int main(int argc, char **argv)
{
int map_flags[] = {0, BPF_F_NO_COMMON_LRU};
const char *dist_file;
int nr_tasks = 1;
int lru_size;
int f;
if (argc < 4) {
printf("Usage: %s <dist-file> <lru-size> <nr-tasks>\n",
argv[0]);
return -1;
}
dist_file = argv[1];
lru_size = atoi(argv[2]);
nr_tasks = atoi(argv[3]);
setbuf(stdout, NULL);
srand(time(NULL));
nr_cpus = bpf_num_possible_cpus();
assert(nr_cpus != -1);
printf("nr_cpus:%d\n\n", nr_cpus);
nr_tasks = min(nr_tasks, nr_cpus);
dist_key_counts = read_keys(dist_file, &dist_keys);
if (!dist_key_counts) {
printf("%s has no key\n", dist_file);
return -1;
}
for (f = 0; f < ARRAY_SIZE(map_flags); f++) {
test_lru_loss0(BPF_MAP_TYPE_LRU_HASH, map_flags[f]);
test_lru_loss1(BPF_MAP_TYPE_LRU_HASH, map_flags[f]);
test_parallel_lru_loss(BPF_MAP_TYPE_LRU_HASH, map_flags[f],
nr_tasks);
test_parallel_lru_dist(BPF_MAP_TYPE_LRU_HASH, map_flags[f],
nr_tasks, lru_size);
printf("\n");
}
free(dist_keys);
return 0;
}
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