1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2020 Wenbo Zhang
3 #include <vmlinux.h>
4 #include <bpf/bpf_helpers.h>
5 #include <bpf/bpf_tracing.h>
6 #include "softirqs.h"
7 #include "bits.bpf.h"
8 #include "maps.bpf.h"
9
10 const volatile bool targ_dist = false;
11 const volatile bool targ_ns = false;
12
13 struct {
14 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
15 __uint(max_entries, 1);
16 __type(key, u32);
17 __type(value, u64);
18 } start SEC(".maps");
19
20 __u64 counts[NR_SOFTIRQS] = {};
21 struct hist hists[NR_SOFTIRQS] = {};
22
23 SEC("tp_btf/softirq_entry")
BPF_PROG(softirq_entry,unsigned int vec_nr)24 int BPF_PROG(softirq_entry, unsigned int vec_nr)
25 {
26 u64 ts = bpf_ktime_get_ns();
27 u32 key = 0;
28
29 bpf_map_update_elem(&start, &key, &ts, 0);
30 return 0;
31 }
32
33 SEC("tp_btf/softirq_exit")
BPF_PROG(softirq_exit,unsigned int vec_nr)34 int BPF_PROG(softirq_exit, unsigned int vec_nr)
35 {
36 u32 key = 0;
37 s64 delta;
38 u64 *tsp;
39
40 if (vec_nr >= NR_SOFTIRQS)
41 return 0;
42 tsp = bpf_map_lookup_elem(&start, &key);
43 if (!tsp || !*tsp)
44 return 0;
45 delta = bpf_ktime_get_ns() - *tsp;
46 if (delta < 0)
47 return 0;
48 if (!targ_ns)
49 delta /= 1000U;
50
51 if (!targ_dist) {
52 __sync_fetch_and_add(&counts[vec_nr], delta);
53 } else {
54 struct hist *hist;
55 u64 slot;
56
57 hist = &hists[vec_nr];
58 slot = log2(delta);
59 if (slot >= MAX_SLOTS)
60 slot = MAX_SLOTS - 1;
61 __sync_fetch_and_add(&hist->slots[slot], 1);
62 }
63
64 return 0;
65 }
66
67 char LICENSE[] SEC("license") = "GPL";
68