tools/testing/selftests/bpf/progs/ringbuf_bench.c

   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 }