1*4882a593Smuzhiyun // SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
2*4882a593Smuzhiyun // Copyright (c) 2020 Facebook
3*4882a593Smuzhiyun #include <vmlinux.h>
4*4882a593Smuzhiyun #include <bpf/bpf_helpers.h>
5*4882a593Smuzhiyun #include <bpf/bpf_tracing.h>
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun /* map of perf event fds, num_cpu * num_metric entries */
8*4882a593Smuzhiyun struct {
9*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
10*4882a593Smuzhiyun __uint(key_size, sizeof(u32));
11*4882a593Smuzhiyun __uint(value_size, sizeof(int));
12*4882a593Smuzhiyun } events SEC(".maps");
13*4882a593Smuzhiyun
14*4882a593Smuzhiyun /* readings at fentry */
15*4882a593Smuzhiyun struct {
16*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
17*4882a593Smuzhiyun __uint(key_size, sizeof(u32));
18*4882a593Smuzhiyun __uint(value_size, sizeof(struct bpf_perf_event_value));
19*4882a593Smuzhiyun } fentry_readings SEC(".maps");
20*4882a593Smuzhiyun
21*4882a593Smuzhiyun /* accumulated readings */
22*4882a593Smuzhiyun struct {
23*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
24*4882a593Smuzhiyun __uint(key_size, sizeof(u32));
25*4882a593Smuzhiyun __uint(value_size, sizeof(struct bpf_perf_event_value));
26*4882a593Smuzhiyun } accum_readings SEC(".maps");
27*4882a593Smuzhiyun
28*4882a593Smuzhiyun /* sample counts, one per cpu */
29*4882a593Smuzhiyun struct {
30*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);
31*4882a593Smuzhiyun __uint(key_size, sizeof(u32));
32*4882a593Smuzhiyun __uint(value_size, sizeof(u64));
33*4882a593Smuzhiyun } counts SEC(".maps");
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun const volatile __u32 num_cpu = 1;
36*4882a593Smuzhiyun const volatile __u32 num_metric = 1;
37*4882a593Smuzhiyun #define MAX_NUM_MATRICS 4
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun SEC("fentry/XXX")
BPF_PROG(fentry_XXX)40*4882a593Smuzhiyun int BPF_PROG(fentry_XXX)
41*4882a593Smuzhiyun {
42*4882a593Smuzhiyun struct bpf_perf_event_value *ptrs[MAX_NUM_MATRICS];
43*4882a593Smuzhiyun u32 key = bpf_get_smp_processor_id();
44*4882a593Smuzhiyun u32 i;
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun /* look up before reading, to reduce error */
47*4882a593Smuzhiyun for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++) {
48*4882a593Smuzhiyun u32 flag = i;
49*4882a593Smuzhiyun
50*4882a593Smuzhiyun ptrs[i] = bpf_map_lookup_elem(&fentry_readings, &flag);
51*4882a593Smuzhiyun if (!ptrs[i])
52*4882a593Smuzhiyun return 0;
53*4882a593Smuzhiyun }
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++) {
56*4882a593Smuzhiyun struct bpf_perf_event_value reading;
57*4882a593Smuzhiyun int err;
58*4882a593Smuzhiyun
59*4882a593Smuzhiyun err = bpf_perf_event_read_value(&events, key, &reading,
60*4882a593Smuzhiyun sizeof(reading));
61*4882a593Smuzhiyun if (err)
62*4882a593Smuzhiyun return 0;
63*4882a593Smuzhiyun *(ptrs[i]) = reading;
64*4882a593Smuzhiyun key += num_cpu;
65*4882a593Smuzhiyun }
66*4882a593Smuzhiyun
67*4882a593Smuzhiyun return 0;
68*4882a593Smuzhiyun }
69*4882a593Smuzhiyun
70*4882a593Smuzhiyun static inline void
fexit_update_maps(u32 id,struct bpf_perf_event_value * after)71*4882a593Smuzhiyun fexit_update_maps(u32 id, struct bpf_perf_event_value *after)
72*4882a593Smuzhiyun {
73*4882a593Smuzhiyun struct bpf_perf_event_value *before, diff;
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun before = bpf_map_lookup_elem(&fentry_readings, &id);
76*4882a593Smuzhiyun /* only account samples with a valid fentry_reading */
77*4882a593Smuzhiyun if (before && before->counter) {
78*4882a593Smuzhiyun struct bpf_perf_event_value *accum;
79*4882a593Smuzhiyun
80*4882a593Smuzhiyun diff.counter = after->counter - before->counter;
81*4882a593Smuzhiyun diff.enabled = after->enabled - before->enabled;
82*4882a593Smuzhiyun diff.running = after->running - before->running;
83*4882a593Smuzhiyun
84*4882a593Smuzhiyun accum = bpf_map_lookup_elem(&accum_readings, &id);
85*4882a593Smuzhiyun if (accum) {
86*4882a593Smuzhiyun accum->counter += diff.counter;
87*4882a593Smuzhiyun accum->enabled += diff.enabled;
88*4882a593Smuzhiyun accum->running += diff.running;
89*4882a593Smuzhiyun }
90*4882a593Smuzhiyun }
91*4882a593Smuzhiyun }
92*4882a593Smuzhiyun
93*4882a593Smuzhiyun SEC("fexit/XXX")
BPF_PROG(fexit_XXX)94*4882a593Smuzhiyun int BPF_PROG(fexit_XXX)
95*4882a593Smuzhiyun {
96*4882a593Smuzhiyun struct bpf_perf_event_value readings[MAX_NUM_MATRICS];
97*4882a593Smuzhiyun u32 cpu = bpf_get_smp_processor_id();
98*4882a593Smuzhiyun u32 i, zero = 0;
99*4882a593Smuzhiyun int err;
100*4882a593Smuzhiyun u64 *count;
101*4882a593Smuzhiyun
102*4882a593Smuzhiyun /* read all events before updating the maps, to reduce error */
103*4882a593Smuzhiyun for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++) {
104*4882a593Smuzhiyun err = bpf_perf_event_read_value(&events, cpu + i * num_cpu,
105*4882a593Smuzhiyun readings + i, sizeof(*readings));
106*4882a593Smuzhiyun if (err)
107*4882a593Smuzhiyun return 0;
108*4882a593Smuzhiyun }
109*4882a593Smuzhiyun count = bpf_map_lookup_elem(&counts, &zero);
110*4882a593Smuzhiyun if (count) {
111*4882a593Smuzhiyun *count += 1;
112*4882a593Smuzhiyun for (i = 0; i < num_metric && i < MAX_NUM_MATRICS; i++)
113*4882a593Smuzhiyun fexit_update_maps(i, &readings[i]);
114*4882a593Smuzhiyun }
115*4882a593Smuzhiyun return 0;
116*4882a593Smuzhiyun }
117*4882a593Smuzhiyun
118*4882a593Smuzhiyun char LICENSE[] SEC("license") = "Dual BSD/GPL";
119