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/* Copyright (c) 2016 Facebook
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of version 2 of the GNU General Public
* License as published by the Free Software Foundation.
*/
#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <fcntl.h>
#include <poll.h>
#include <sys/ioctl.h>
#include <linux/perf_event.h>
#include <linux/bpf.h>
#include <signal.h>
#include <assert.h>
#include <errno.h>
#include <sys/resource.h>
#include "libbpf.h"
#include "bpf_load.h"
#define SAMPLE_FREQ 50
static bool sys_read_seen, sys_write_seen;
static void print_ksym(__u64 addr)
{
struct ksym *sym;
if (!addr)
return;
sym = ksym_search(addr);
printf("%s;", sym->name);
if (!strcmp(sym->name, "sys_read"))
sys_read_seen = true;
else if (!strcmp(sym->name, "sys_write"))
sys_write_seen = true;
}
static void print_addr(__u64 addr)
{
if (!addr)
return;
printf("%llx;", addr);
}
#define TASK_COMM_LEN 16
struct key_t {
char comm[TASK_COMM_LEN];
__u32 kernstack;
__u32 userstack;
};
static void print_stack(struct key_t *key, __u64 count)
{
__u64 ip[PERF_MAX_STACK_DEPTH] = {};
static bool warned;
int i;
printf("%3lld %s;", count, key->comm);
if (bpf_lookup_elem(map_fd[1], &key->kernstack, ip) != 0) {
printf("---;");
} else {
for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
print_ksym(ip[i]);
}
printf("-;");
if (bpf_lookup_elem(map_fd[1], &key->userstack, ip) != 0) {
printf("---;");
} else {
for (i = PERF_MAX_STACK_DEPTH - 1; i >= 0; i--)
print_addr(ip[i]);
}
printf("\n");
if (key->kernstack == -EEXIST && !warned) {
printf("stackmap collisions seen. Consider increasing size\n");
warned = true;
} else if ((int)key->kernstack < 0 && (int)key->userstack < 0) {
printf("err stackid %d %d\n", key->kernstack, key->userstack);
}
}
static void int_exit(int sig)
{
kill(0, SIGKILL);
exit(0);
}
static void print_stacks(void)
{
struct key_t key = {}, next_key;
__u64 value;
__u32 stackid = 0, next_id;
int fd = map_fd[0], stack_map = map_fd[1];
sys_read_seen = sys_write_seen = false;
while (bpf_get_next_key(fd, &key, &next_key) == 0) {
bpf_lookup_elem(fd, &next_key, &value);
print_stack(&next_key, value);
bpf_delete_elem(fd, &next_key);
key = next_key;
}
if (!sys_read_seen || !sys_write_seen) {
printf("BUG kernel stack doesn't contain sys_read() and sys_write()\n");
int_exit(0);
}
/* clear stack map */
while (bpf_get_next_key(stack_map, &stackid, &next_id) == 0) {
bpf_delete_elem(stack_map, &next_id);
stackid = next_id;
}
}
static void test_perf_event_all_cpu(struct perf_event_attr *attr)
{
int nr_cpus = sysconf(_SC_NPROCESSORS_CONF);
int *pmu_fd = malloc(nr_cpus * sizeof(int));
int i;
/* open perf_event on all cpus */
for (i = 0; i < nr_cpus; i++) {
pmu_fd[i] = perf_event_open(attr, -1, i, -1, 0);
if (pmu_fd[i] < 0) {
printf("perf_event_open failed\n");
goto all_cpu_err;
}
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd[i], PERF_EVENT_IOC_ENABLE, 0) == 0);
}
system("dd if=/dev/zero of=/dev/null count=5000k");
print_stacks();
all_cpu_err:
for (i--; i >= 0; i--)
close(pmu_fd[i]);
free(pmu_fd);
}
static void test_perf_event_task(struct perf_event_attr *attr)
{
int pmu_fd;
/* open task bound event */
pmu_fd = perf_event_open(attr, 0, -1, -1, 0);
if (pmu_fd < 0) {
printf("perf_event_open failed\n");
return;
}
assert(ioctl(pmu_fd, PERF_EVENT_IOC_SET_BPF, prog_fd[0]) == 0);
assert(ioctl(pmu_fd, PERF_EVENT_IOC_ENABLE, 0) == 0);
system("dd if=/dev/zero of=/dev/null count=5000k");
print_stacks();
close(pmu_fd);
}
static void test_bpf_perf_event(void)
{
struct perf_event_attr attr_type_hw = {
.sample_freq = SAMPLE_FREQ,
.freq = 1,
.type = PERF_TYPE_HARDWARE,
.config = PERF_COUNT_HW_CPU_CYCLES,
.inherit = 1,
};
struct perf_event_attr attr_type_sw = {
.sample_freq = SAMPLE_FREQ,
.freq = 1,
.type = PERF_TYPE_SOFTWARE,
.config = PERF_COUNT_SW_CPU_CLOCK,
.inherit = 1,
};
test_perf_event_all_cpu(&attr_type_hw);
test_perf_event_task(&attr_type_hw);
test_perf_event_all_cpu(&attr_type_sw);
test_perf_event_task(&attr_type_sw);
}
int main(int argc, char **argv)
{
struct rlimit r = {RLIM_INFINITY, RLIM_INFINITY};
char filename[256];
snprintf(filename, sizeof(filename), "%s_kern.o", argv[0]);
setrlimit(RLIMIT_MEMLOCK, &r);
signal(SIGINT, int_exit);
if (load_kallsyms()) {
printf("failed to process /proc/kallsyms\n");
return 1;
}
if (load_bpf_file(filename)) {
printf("%s", bpf_log_buf);
return 2;
}
if (fork() == 0) {
read_trace_pipe();
return 0;
}
test_bpf_perf_event();
int_exit(0);
return 0;
}
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