blob: c0aa5a9b9c48ce4213cd13b90c11ebcc0892981a [file] [log] [blame]
Alexei Starovoitova6ffe7b2016-02-17 19:58:59 -08001/* Copyright (c) 2016 Facebook
2 *
3 * This program is free software; you can redistribute it and/or
4 * modify it under the terms of version 2 of the GNU General Public
5 * License as published by the Free Software Foundation.
6 */
7#include <uapi/linux/bpf.h>
8#include "bpf_helpers.h"
9#include <uapi/linux/ptrace.h>
10#include <uapi/linux/perf_event.h>
11#include <linux/version.h>
12#include <linux/sched.h>
13
14#define _(P) ({typeof(P) val = 0; bpf_probe_read(&val, sizeof(val), &P); val;})
15
16#define MINBLOCK_US 1
17
18struct key_t {
19 char waker[TASK_COMM_LEN];
20 char target[TASK_COMM_LEN];
21 u32 wret;
22 u32 tret;
23};
24
25struct bpf_map_def SEC("maps") counts = {
26 .type = BPF_MAP_TYPE_HASH,
27 .key_size = sizeof(struct key_t),
28 .value_size = sizeof(u64),
29 .max_entries = 10000,
30};
31
32struct bpf_map_def SEC("maps") start = {
33 .type = BPF_MAP_TYPE_HASH,
34 .key_size = sizeof(u32),
35 .value_size = sizeof(u64),
36 .max_entries = 10000,
37};
38
39struct wokeby_t {
40 char name[TASK_COMM_LEN];
41 u32 ret;
42};
43
44struct bpf_map_def SEC("maps") wokeby = {
45 .type = BPF_MAP_TYPE_HASH,
46 .key_size = sizeof(u32),
47 .value_size = sizeof(struct wokeby_t),
48 .max_entries = 10000,
49};
50
51struct bpf_map_def SEC("maps") stackmap = {
52 .type = BPF_MAP_TYPE_STACK_TRACE,
53 .key_size = sizeof(u32),
54 .value_size = PERF_MAX_STACK_DEPTH * sizeof(u64),
55 .max_entries = 10000,
56};
57
58#define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP)
59
60SEC("kprobe/try_to_wake_up")
61int waker(struct pt_regs *ctx)
62{
63 struct task_struct *p = (void *) PT_REGS_PARM1(ctx);
64 struct wokeby_t woke = {};
65 u32 pid;
66
67 pid = _(p->pid);
68
69 bpf_get_current_comm(&woke.name, sizeof(woke.name));
70 woke.ret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS);
71
72 bpf_map_update_elem(&wokeby, &pid, &woke, BPF_ANY);
73 return 0;
74}
75
76static inline int update_counts(struct pt_regs *ctx, u32 pid, u64 delta)
77{
78 struct key_t key = {};
79 struct wokeby_t *woke;
80 u64 zero = 0, *val;
81
82 bpf_get_current_comm(&key.target, sizeof(key.target));
83 key.tret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS);
84
85 woke = bpf_map_lookup_elem(&wokeby, &pid);
86 if (woke) {
87 key.wret = woke->ret;
88 __builtin_memcpy(&key.waker, woke->name, TASK_COMM_LEN);
89 bpf_map_delete_elem(&wokeby, &pid);
90 }
91
92 val = bpf_map_lookup_elem(&counts, &key);
93 if (!val) {
94 bpf_map_update_elem(&counts, &key, &zero, BPF_NOEXIST);
95 val = bpf_map_lookup_elem(&counts, &key);
96 if (!val)
97 return 0;
98 }
99 (*val) += delta;
100 return 0;
101}
102
103SEC("kprobe/finish_task_switch")
104int oncpu(struct pt_regs *ctx)
105{
106 struct task_struct *p = (void *) PT_REGS_PARM1(ctx);
107 u64 delta, ts, *tsp;
108 u32 pid;
109
110 /* record previous thread sleep time */
111 pid = _(p->pid);
112 ts = bpf_ktime_get_ns();
113 bpf_map_update_elem(&start, &pid, &ts, BPF_ANY);
114
115 /* calculate current thread's delta time */
116 pid = bpf_get_current_pid_tgid();
117 tsp = bpf_map_lookup_elem(&start, &pid);
118 if (!tsp)
119 /* missed start or filtered */
120 return 0;
121
122 delta = bpf_ktime_get_ns() - *tsp;
123 bpf_map_delete_elem(&start, &pid);
124 delta = delta / 1000;
125 if (delta < MINBLOCK_US)
126 return 0;
127
128 return update_counts(ctx, pid, delta);
129}
130char _license[] SEC("license") = "GPL";
131u32 _version SEC("version") = LINUX_VERSION_CODE;