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 } 62