// 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)); __uint(max_entries, 1); } 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)); __uint(max_entries, 1); } accum_readings SEC(".maps"); const volatile __u32 num_cpu = 1; SEC("fentry/XXX") int BPF_PROG(fentry_XXX) { __u32 key = bpf_get_smp_processor_id(); struct bpf_perf_event_value *ptr; __u32 zero = 0; long err; /* look up before reading, to reduce error */ ptr = bpf_map_lookup_elem(&fentry_readings, &zero); if (!ptr) return 0; err = bpf_perf_event_read_value(&events, key, ptr, sizeof(*ptr)); if (err) return 0; return 0; } static inline void fexit_update_maps(struct bpf_perf_event_value *after) { struct bpf_perf_event_value *before, diff; __u32 zero = 0; before = bpf_map_lookup_elem(&fentry_readings, &zero); /* 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, &zero); 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 reading; __u32 cpu = bpf_get_smp_processor_id(); int err; /* read all events before updating the maps, to reduce error */ err = bpf_perf_event_read_value(&events, cpu, &reading, sizeof(reading)); if (err) return 0; fexit_update_maps(&reading); return 0; } char LICENSE[] SEC("license") = "Dual BSD/GPL";