ringbuf_bench.c

 1// SPDX-License-Identifier: GPL-2.0
 2// Copyright (c) 2020 Facebook
 3
 4#include <stdbool.h>
 5#include <linux/bpf.h>
 6#include <stdint.h>
 7#include <bpf/bpf_helpers.h>
 8#include "bpf_misc.h"
 9
10char _license[] SEC("license") = "GPL";
11
12struct {
13	__uint(type, BPF_MAP_TYPE_RINGBUF);
14} ringbuf SEC(".maps");
15
16const volatile int batch_cnt = 0;
17const volatile long use_output = 0;
18const volatile bool bench_producer = false;
19
20long sample_val = 42;
21long dropped __attribute__((aligned(128))) = 0;
22long hits __attribute__((aligned(128))) = 0;
23
24const volatile long wakeup_data_size = 0;
25
26static __always_inline long get_flags()
27{
28	long sz;
29
30	if (bench_producer)
31		return BPF_RB_NO_WAKEUP;
32
33	if (!wakeup_data_size)
34		return 0;
35
36	sz = bpf_ringbuf_query(&ringbuf, BPF_RB_AVAIL_DATA);
37	return sz >= wakeup_data_size ? BPF_RB_FORCE_WAKEUP : BPF_RB_NO_WAKEUP;
38}
39
40SEC("fentry/" SYS_PREFIX "sys_getpgid")
41int bench_ringbuf(void *ctx)
42{
43	long *sample, flags;
44	int i;
45
46	if (!use_output) {
47		for (i = 0; i < batch_cnt; i++) {
48			sample = bpf_ringbuf_reserve(&ringbuf,
49					             sizeof(sample_val), 0);
50			if (!sample) {
51				__sync_add_and_fetch(&dropped, 1);
52			} else {
53				*sample = sample_val;
54				flags = get_flags();
55				bpf_ringbuf_submit(sample, flags);
56				if (bench_producer)
57					__sync_add_and_fetch(&hits, 1);
58			}
59		}
60	} else {
61		for (i = 0; i < batch_cnt; i++) {
62			flags = get_flags();
63			if (bpf_ringbuf_output(&ringbuf, &sample_val,
64					       sizeof(sample_val), flags))
65				__sync_add_and_fetch(&dropped, 1);
66			else if (bench_producer)
67				__sync_add_and_fetch(&hits, 1);
68
69		}
70	}
71	return 0;
72}