1 | /* 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 "vmlinux.h" |
8 | #include <linux/version.h> |
9 | #include <bpf/bpf_helpers.h> |
10 | #include <bpf/bpf_tracing.h> |
11 | #include <bpf/bpf_core_read.h> |
12 | |
13 | #ifndef PERF_MAX_STACK_DEPTH |
14 | #define PERF_MAX_STACK_DEPTH 127 |
15 | #endif |
16 | |
17 | #define MINBLOCK_US 1 |
18 | #define MAX_ENTRIES 10000 |
19 | |
20 | struct key_t { |
21 | char waker[TASK_COMM_LEN]; |
22 | char target[TASK_COMM_LEN]; |
23 | u32 wret; |
24 | u32 tret; |
25 | }; |
26 | |
27 | struct { |
28 | __uint(type, BPF_MAP_TYPE_HASH); |
29 | __type(key, struct key_t); |
30 | __type(value, u64); |
31 | __uint(max_entries, MAX_ENTRIES); |
32 | } counts SEC(".maps" ); |
33 | |
34 | struct { |
35 | __uint(type, BPF_MAP_TYPE_HASH); |
36 | __type(key, u32); |
37 | __type(value, u64); |
38 | __uint(max_entries, MAX_ENTRIES); |
39 | } start SEC(".maps" ); |
40 | |
41 | struct wokeby_t { |
42 | char name[TASK_COMM_LEN]; |
43 | u32 ret; |
44 | }; |
45 | |
46 | struct { |
47 | __uint(type, BPF_MAP_TYPE_HASH); |
48 | __type(key, u32); |
49 | __type(value, struct wokeby_t); |
50 | __uint(max_entries, MAX_ENTRIES); |
51 | } wokeby SEC(".maps" ); |
52 | |
53 | struct { |
54 | __uint(type, BPF_MAP_TYPE_STACK_TRACE); |
55 | __uint(key_size, sizeof(u32)); |
56 | __uint(value_size, PERF_MAX_STACK_DEPTH * sizeof(u64)); |
57 | __uint(max_entries, MAX_ENTRIES); |
58 | } stackmap SEC(".maps" ); |
59 | |
60 | #define STACKID_FLAGS (0 | BPF_F_FAST_STACK_CMP) |
61 | |
62 | SEC("kprobe/try_to_wake_up" ) |
63 | int waker(struct pt_regs *ctx) |
64 | { |
65 | struct task_struct *p = (void *)PT_REGS_PARM1_CORE(ctx); |
66 | u32 pid = BPF_CORE_READ(p, pid); |
67 | struct wokeby_t woke; |
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 | |
76 | static inline int update_counts(void *ctx, u32 pid, u64 delta) |
77 | { |
78 | struct wokeby_t *woke; |
79 | u64 zero = 0, *val; |
80 | struct key_t key; |
81 | |
82 | __builtin_memset(&key.waker, 0, sizeof(key.waker)); |
83 | bpf_get_current_comm(&key.target, sizeof(key.target)); |
84 | key.tret = bpf_get_stackid(ctx, &stackmap, STACKID_FLAGS); |
85 | key.wret = 0; |
86 | |
87 | woke = bpf_map_lookup_elem(&wokeby, &pid); |
88 | if (woke) { |
89 | key.wret = woke->ret; |
90 | __builtin_memcpy(&key.waker, woke->name, sizeof(key.waker)); |
91 | bpf_map_delete_elem(&wokeby, &pid); |
92 | } |
93 | |
94 | val = bpf_map_lookup_elem(&counts, &key); |
95 | if (!val) { |
96 | bpf_map_update_elem(&counts, &key, &zero, BPF_NOEXIST); |
97 | val = bpf_map_lookup_elem(&counts, &key); |
98 | if (!val) |
99 | return 0; |
100 | } |
101 | (*val) += delta; |
102 | return 0; |
103 | } |
104 | |
105 | #if 1 |
106 | /* taken from /sys/kernel/tracing/events/sched/sched_switch/format */ |
107 | SEC("tracepoint/sched/sched_switch" ) |
108 | int oncpu(struct trace_event_raw_sched_switch *ctx) |
109 | { |
110 | /* record previous thread sleep time */ |
111 | u32 pid = ctx->prev_pid; |
112 | #else |
113 | SEC("kprobe.multi/finish_task_switch*" ) |
114 | int oncpu(struct pt_regs *ctx) |
115 | { |
116 | struct task_struct *p = (void *)PT_REGS_PARM1_CORE(ctx); |
117 | /* record previous thread sleep time */ |
118 | u32 pid = BPF_CORE_READ(p, pid); |
119 | #endif |
120 | u64 delta, ts, *tsp; |
121 | |
122 | ts = bpf_ktime_get_ns(); |
123 | bpf_map_update_elem(&start, &pid, &ts, BPF_ANY); |
124 | |
125 | /* calculate current thread's delta time */ |
126 | pid = bpf_get_current_pid_tgid(); |
127 | tsp = bpf_map_lookup_elem(&start, &pid); |
128 | if (!tsp) |
129 | /* missed start or filtered */ |
130 | return 0; |
131 | |
132 | delta = bpf_ktime_get_ns() - *tsp; |
133 | bpf_map_delete_elem(&start, &pid); |
134 | delta = delta / 1000; |
135 | if (delta < MINBLOCK_US) |
136 | return 0; |
137 | |
138 | return update_counts(ctx, pid, delta); |
139 | } |
140 | char _license[] SEC("license" ) = "GPL" ; |
141 | u32 _version SEC("version" ) = LINUX_VERSION_CODE; |
142 | |