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 #include "bpf_misc.h"
   8
   9 char _license[] SEC("license") = "GPL";
  10
  11 struct {
  12         __uint(type, BPF_MAP_TYPE_RINGBUF);
  13 } ringbuf SEC(".maps");
  14
  15 const volatile int batch_cnt = 0;
  16 const volatile long use_output = 0;
  17
  18 long sample_val = 42;
  19 long dropped __attribute__((aligned(128))) = 0;
  20
  21 const volatile long wakeup_data_size = 0;
  22
  23 static __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
  34 SEC("fentry/" SYS_PREFIX "sys_getpgid")
  35 int 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 }