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 
8 char _license[] SEC("license") = "GPL";
9 
10 struct {
11 	__uint(type, BPF_MAP_TYPE_RINGBUF);
12 } ringbuf SEC(".maps");
13 
14 const volatile int batch_cnt = 0;
15 const volatile long use_output = 0;
16 
17 long sample_val = 42;
18 long dropped __attribute__((aligned(128))) = 0;
19 
20 const volatile long wakeup_data_size = 0;
21 
22 static __always_inline long get_flags()
23 {
24 	long sz;
25 
26 	if (!wakeup_data_size)
27 		return 0;
28 
29 	sz = bpf_ringbuf_query(&ringbuf, BPF_RB_AVAIL_DATA);
30 	return sz >= wakeup_data_size ? BPF_RB_FORCE_WAKEUP : BPF_RB_NO_WAKEUP;
31 }
32 
33 SEC("fentry/__x64_sys_getpgid")
34 int bench_ringbuf(void *ctx)
35 {
36 	long *sample, flags;
37 	int i;
38 
39 	if (!use_output) {
40 		for (i = 0; i < batch_cnt; i++) {
41 			sample = bpf_ringbuf_reserve(&ringbuf,
42 					             sizeof(sample_val), 0);
43 			if (!sample) {
44 				__sync_add_and_fetch(&dropped, 1);
45 			} else {
46 				*sample = sample_val;
47 				flags = get_flags();
48 				bpf_ringbuf_submit(sample, flags);
49 			}
50 		}
51 	} else {
52 		for (i = 0; i < batch_cnt; i++) {
53 			flags = get_flags();
54 			if (bpf_ringbuf_output(&ringbuf, &sample_val,
55 					       sizeof(sample_val), flags))
56 				__sync_add_and_fetch(&dropped, 1);
57 		}
58 	}
59 	return 0;
60 }
61