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