1// SPDX-License-Identifier: GPL-2.0
2// Copyright (c) 2020 Facebook
3
4#include <linux/bpf.h>
5#include <stdint.h>
6#include <bpf/bpf_helpers.h>
7#include "bpf_misc.h"
8
9char _license[] SEC("license") = "GPL";
10
11struct {
12	__uint(type, BPF_MAP_TYPE_RINGBUF);
13} ringbuf SEC(".maps");
14
15const volatile int batch_cnt = 0;
16const volatile long use_output = 0;
17
18long sample_val = 42;
19long dropped __attribute__((aligned(128))) = 0;
20
21const volatile long wakeup_data_size = 0;
22
23static __always_inline long get_flags()
24{
25	long sz;
26
27	if (!wakeup_data_size)
28		return 0;
29
30	sz = bpf_ringbuf_query(&ringbuf, BPF_RB_AVAIL_DATA);
31	return sz >= wakeup_data_size ? BPF_RB_FORCE_WAKEUP : BPF_RB_NO_WAKEUP;
32}
33
34SEC("fentry/" SYS_PREFIX "sys_getpgid")
35int bench_ringbuf(void *ctx)
36{
37	long *sample, flags;
38	int i;
39
40	if (!use_output) {
41		for (i = 0; i < batch_cnt; i++) {
42			sample = bpf_ringbuf_reserve(&ringbuf,
43					             sizeof(sample_val), 0);
44			if (!sample) {
45				__sync_add_and_fetch(&dropped, 1);
46			} else {
47				*sample = sample_val;
48				flags = get_flags();
49				bpf_ringbuf_submit(sample, flags);
50			}
51		}
52	} else {
53		for (i = 0; i < batch_cnt; i++) {
54			flags = get_flags();
55			if (bpf_ringbuf_output(&ringbuf, &sample_val,
56					       sizeof(sample_val), flags))
57				__sync_add_and_fetch(&dropped, 1);
58		}
59	}
60	return 0;
61}
62