93 lines
2.2 KiB
C
93 lines
2.2 KiB
C
// 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";
|