https://github.com/torvalds/linux
Tip revision: e4e737bb5c170df6135a127739a9e6148ee3da82 authored by Linus Torvalds on 20 September 2021, 00:28:22 UTC
Linux 5.15-rc2
Linux 5.15-rc2
Tip revision: e4e737b
test_overhead_user.c
// SPDX-License-Identifier: GPL-2.0-only
/* Copyright (c) 2016 Facebook
*/
#define _GNU_SOURCE
#include <sched.h>
#include <errno.h>
#include <stdio.h>
#include <sys/types.h>
#include <asm/unistd.h>
#include <fcntl.h>
#include <unistd.h>
#include <assert.h>
#include <sys/wait.h>
#include <stdlib.h>
#include <signal.h>
#include <linux/bpf.h>
#include <string.h>
#include <time.h>
#include <sys/resource.h>
#include <bpf/bpf.h>
#include <bpf/libbpf.h>
#define MAX_CNT 1000000
static struct bpf_link *links[2];
static struct bpf_object *obj;
static int cnt;
static __u64 time_get_ns(void)
{
struct timespec ts;
clock_gettime(CLOCK_MONOTONIC, &ts);
return ts.tv_sec * 1000000000ull + ts.tv_nsec;
}
static void test_task_rename(int cpu)
{
__u64 start_time;
char buf[] = "test\n";
int i, fd;
fd = open("/proc/self/comm", O_WRONLY|O_TRUNC);
if (fd < 0) {
printf("couldn't open /proc\n");
exit(1);
}
start_time = time_get_ns();
for (i = 0; i < MAX_CNT; i++) {
if (write(fd, buf, sizeof(buf)) < 0) {
printf("task rename failed: %s\n", strerror(errno));
close(fd);
return;
}
}
printf("task_rename:%d: %lld events per sec\n",
cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
close(fd);
}
static void test_urandom_read(int cpu)
{
__u64 start_time;
char buf[4];
int i, fd;
fd = open("/dev/urandom", O_RDONLY);
if (fd < 0) {
printf("couldn't open /dev/urandom\n");
exit(1);
}
start_time = time_get_ns();
for (i = 0; i < MAX_CNT; i++) {
if (read(fd, buf, sizeof(buf)) < 0) {
printf("failed to read from /dev/urandom: %s\n", strerror(errno));
close(fd);
return;
}
}
printf("urandom_read:%d: %lld events per sec\n",
cpu, MAX_CNT * 1000000000ll / (time_get_ns() - start_time));
close(fd);
}
static void loop(int cpu, int flags)
{
cpu_set_t cpuset;
CPU_ZERO(&cpuset);
CPU_SET(cpu, &cpuset);
sched_setaffinity(0, sizeof(cpuset), &cpuset);
if (flags & 1)
test_task_rename(cpu);
if (flags & 2)
test_urandom_read(cpu);
}
static void run_perf_test(int tasks, int flags)
{
pid_t pid[tasks];
int i;
for (i = 0; i < tasks; i++) {
pid[i] = fork();
if (pid[i] == 0) {
loop(i, flags);
exit(0);
} else if (pid[i] == -1) {
printf("couldn't spawn #%d process\n", i);
exit(1);
}
}
for (i = 0; i < tasks; i++) {
int status;
assert(waitpid(pid[i], &status, 0) == pid[i]);
assert(status == 0);
}
}
static int load_progs(char *filename)
{
struct bpf_program *prog;
int err = 0;
obj = bpf_object__open_file(filename, NULL);
err = libbpf_get_error(obj);
if (err < 0) {
fprintf(stderr, "ERROR: opening BPF object file failed\n");
return err;
}
/* load BPF program */
err = bpf_object__load(obj);
if (err < 0) {
fprintf(stderr, "ERROR: loading BPF object file failed\n");
return err;
}
bpf_object__for_each_program(prog, obj) {
links[cnt] = bpf_program__attach(prog);
err = libbpf_get_error(links[cnt]);
if (err < 0) {
fprintf(stderr, "ERROR: bpf_program__attach failed\n");
links[cnt] = NULL;
return err;
}
cnt++;
}
return err;
}
static void unload_progs(void)
{
while (cnt)
bpf_link__destroy(links[--cnt]);
bpf_object__close(obj);
}
int main(int argc, char **argv)
{
int num_cpu = sysconf(_SC_NPROCESSORS_ONLN);
int test_flags = ~0;
char filename[256];
int err = 0;
if (argc > 1)
test_flags = atoi(argv[1]) ? : test_flags;
if (argc > 2)
num_cpu = atoi(argv[2]) ? : num_cpu;
if (test_flags & 0x3) {
printf("BASE\n");
run_perf_test(num_cpu, test_flags);
}
if (test_flags & 0xC) {
snprintf(filename, sizeof(filename),
"%s_kprobe_kern.o", argv[0]);
printf("w/KPROBE\n");
err = load_progs(filename);
if (!err)
run_perf_test(num_cpu, test_flags >> 2);
unload_progs();
}
if (test_flags & 0x30) {
snprintf(filename, sizeof(filename),
"%s_tp_kern.o", argv[0]);
printf("w/TRACEPOINT\n");
err = load_progs(filename);
if (!err)
run_perf_test(num_cpu, test_flags >> 4);
unload_progs();
}
if (test_flags & 0xC0) {
snprintf(filename, sizeof(filename),
"%s_raw_tp_kern.o", argv[0]);
printf("w/RAW_TRACEPOINT\n");
err = load_progs(filename);
if (!err)
run_perf_test(num_cpu, test_flags >> 6);
unload_progs();
}
return err;
}