| // SPDX-License-Identifier: GPL-2.0 |
| /* Copyright (c) 2021 Google LLC. */ |
| #include "vmlinux.h" |
| #include <bpf/bpf_core_read.h> |
| #include <bpf/bpf_helpers.h> |
| #include <bpf/bpf_tracing.h> |
| #include "funclatency.h" |
| #include "bits.bpf.h" |
| |
| const volatile pid_t targ_tgid = 0; |
| const volatile int units = 0; |
| |
| /* key: pid. value: start time */ |
| struct { |
| __uint(type, BPF_MAP_TYPE_HASH); |
| __uint(max_entries, MAX_PIDS); |
| __type(key, u32); |
| __type(value, u64); |
| } starts SEC(".maps"); |
| |
| __u32 hist[MAX_SLOTS] = {}; |
| |
| SEC("kprobe/dummy_kprobe") |
| int BPF_KPROBE(dummy_kprobe) |
| { |
| u64 id = bpf_get_current_pid_tgid(); |
| u32 tgid = id >> 32; |
| u32 pid = id; |
| u64 nsec; |
| |
| if (targ_tgid && targ_tgid != tgid) |
| return 0; |
| nsec = bpf_ktime_get_ns(); |
| bpf_map_update_elem(&starts, &pid, &nsec, BPF_ANY); |
| |
| return 0; |
| } |
| |
| SEC("kretprobe/dummy_kretprobe") |
| int BPF_KRETPROBE(dummy_kretprobe) |
| { |
| u64 *start; |
| u64 nsec = bpf_ktime_get_ns(); |
| u64 id = bpf_get_current_pid_tgid(); |
| u32 pid = id; |
| u64 slot, delta; |
| |
| start = bpf_map_lookup_elem(&starts, &pid); |
| if (!start) |
| return 0; |
| |
| delta = nsec - *start; |
| |
| switch (units) { |
| case USEC: |
| delta /= 1000; |
| break; |
| case MSEC: |
| delta /= 1000000; |
| break; |
| } |
| |
| slot = log2l(delta); |
| if (slot >= MAX_SLOTS) |
| slot = MAX_SLOTS - 1; |
| __sync_fetch_and_add(&hist[slot], 1); |
| |
| return 0; |
| } |
| |
| char LICENSE[] SEC("license") = "GPL"; |