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1// SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)2// Copyright (c) 2020 Facebook3#include <vmlinux.h>4#include <bpf/bpf_helpers.h>5#include <bpf/bpf_tracing.h>6 7struct bpf_perf_event_value___local {8 __u64 counter;9 __u64 enabled;10 __u64 running;11} __attribute__((preserve_access_index));12 13/* map of perf event fds, num_cpu * num_metric entries */14struct {15 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);16 __uint(key_size, sizeof(u32));17 __uint(value_size, sizeof(int));18} events SEC(".maps");19 20/* readings at fentry */21struct {22 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);23 __uint(key_size, sizeof(u32));24 __uint(value_size, sizeof(struct bpf_perf_event_value___local));25} fentry_readings SEC(".maps");26 27/* accumulated readings */28struct {29 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);30 __uint(key_size, sizeof(u32));31 __uint(value_size, sizeof(struct bpf_perf_event_value___local));32} accum_readings SEC(".maps");33 34/* sample counts, one per cpu */35struct {36 __uint(type, BPF_MAP_TYPE_PERCPU_ARRAY);37 __uint(key_size, sizeof(u32));38 __uint(value_size, sizeof(u64));39} counts SEC(".maps");40 41const volatile __u32 num_cpu = 1;42const volatile __u32 num_metric = 1;43#define MAX_NUM_METRICS 444 45SEC("fentry/XXX")46int BPF_PROG(fentry_XXX)47{48 struct bpf_perf_event_value___local *ptrs[MAX_NUM_METRICS];49 u32 key = bpf_get_smp_processor_id();50 u32 i;51 52 /* look up before reading, to reduce error */53 for (i = 0; i < num_metric && i < MAX_NUM_METRICS; i++) {54 u32 flag = i;55 56 ptrs[i] = bpf_map_lookup_elem(&fentry_readings, &flag);57 if (!ptrs[i])58 return 0;59 }60 61 for (i = 0; i < num_metric && i < MAX_NUM_METRICS; i++) {62 struct bpf_perf_event_value___local reading;63 int err;64 65 err = bpf_perf_event_read_value(&events, key, (void *)&reading,66 sizeof(reading));67 if (err)68 return 0;69 *(ptrs[i]) = reading;70 key += num_cpu;71 }72 73 return 0;74}75 76static inline void77fexit_update_maps(u32 id, struct bpf_perf_event_value___local *after)78{79 struct bpf_perf_event_value___local *before, diff;80 81 before = bpf_map_lookup_elem(&fentry_readings, &id);82 /* only account samples with a valid fentry_reading */83 if (before && before->counter) {84 struct bpf_perf_event_value___local *accum;85 86 diff.counter = after->counter - before->counter;87 diff.enabled = after->enabled - before->enabled;88 diff.running = after->running - before->running;89 90 accum = bpf_map_lookup_elem(&accum_readings, &id);91 if (accum) {92 accum->counter += diff.counter;93 accum->enabled += diff.enabled;94 accum->running += diff.running;95 }96 }97}98 99SEC("fexit/XXX")100int BPF_PROG(fexit_XXX)101{102 struct bpf_perf_event_value___local readings[MAX_NUM_METRICS];103 u32 cpu = bpf_get_smp_processor_id();104 u32 i, zero = 0;105 int err;106 u64 *count;107 108 /* read all events before updating the maps, to reduce error */109 for (i = 0; i < num_metric && i < MAX_NUM_METRICS; i++) {110 err = bpf_perf_event_read_value(&events, cpu + i * num_cpu,111 (void *)(readings + i),112 sizeof(*readings));113 if (err)114 return 0;115 }116 count = bpf_map_lookup_elem(&counts, &zero);117 if (count) {118 *count += 1;119 for (i = 0; i < num_metric && i < MAX_NUM_METRICS; i++)120 fexit_update_maps(i, &readings[i]);121 }122 return 0;123}124 125char LICENSE[] SEC("license") = "Dual BSD/GPL";126