1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0
2*4882a593Smuzhiyun // Copyright (c) 2019 Facebook
3*4882a593Smuzhiyun #include "vmlinux.h"
4*4882a593Smuzhiyun #include <bpf/bpf_helpers.h>
5*4882a593Smuzhiyun #include "runqslower.h"
6*4882a593Smuzhiyun
7*4882a593Smuzhiyun #define TASK_RUNNING 0
8*4882a593Smuzhiyun #define BPF_F_CURRENT_CPU 0xffffffffULL
9*4882a593Smuzhiyun
10*4882a593Smuzhiyun const volatile __u64 min_us = 0;
11*4882a593Smuzhiyun const volatile pid_t targ_pid = 0;
12*4882a593Smuzhiyun
13*4882a593Smuzhiyun struct {
14*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_HASH);
15*4882a593Smuzhiyun __uint(max_entries, 10240);
16*4882a593Smuzhiyun __type(key, u32);
17*4882a593Smuzhiyun __type(value, u64);
18*4882a593Smuzhiyun } start SEC(".maps");
19*4882a593Smuzhiyun
20*4882a593Smuzhiyun struct {
21*4882a593Smuzhiyun __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
22*4882a593Smuzhiyun __uint(key_size, sizeof(u32));
23*4882a593Smuzhiyun __uint(value_size, sizeof(u32));
24*4882a593Smuzhiyun } events SEC(".maps");
25*4882a593Smuzhiyun
26*4882a593Smuzhiyun /* record enqueue timestamp */
27*4882a593Smuzhiyun __always_inline
trace_enqueue(u32 tgid,u32 pid)28*4882a593Smuzhiyun static int trace_enqueue(u32 tgid, u32 pid)
29*4882a593Smuzhiyun {
30*4882a593Smuzhiyun u64 ts;
31*4882a593Smuzhiyun
32*4882a593Smuzhiyun if (!pid || (targ_pid && targ_pid != pid))
33*4882a593Smuzhiyun return 0;
34*4882a593Smuzhiyun
35*4882a593Smuzhiyun ts = bpf_ktime_get_ns();
36*4882a593Smuzhiyun bpf_map_update_elem(&start, &pid, &ts, 0);
37*4882a593Smuzhiyun return 0;
38*4882a593Smuzhiyun }
39*4882a593Smuzhiyun
40*4882a593Smuzhiyun SEC("tp_btf/sched_wakeup")
handle__sched_wakeup(u64 * ctx)41*4882a593Smuzhiyun int handle__sched_wakeup(u64 *ctx)
42*4882a593Smuzhiyun {
43*4882a593Smuzhiyun /* TP_PROTO(struct task_struct *p) */
44*4882a593Smuzhiyun struct task_struct *p = (void *)ctx[0];
45*4882a593Smuzhiyun
46*4882a593Smuzhiyun return trace_enqueue(p->tgid, p->pid);
47*4882a593Smuzhiyun }
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun SEC("tp_btf/sched_wakeup_new")
handle__sched_wakeup_new(u64 * ctx)50*4882a593Smuzhiyun int handle__sched_wakeup_new(u64 *ctx)
51*4882a593Smuzhiyun {
52*4882a593Smuzhiyun /* TP_PROTO(struct task_struct *p) */
53*4882a593Smuzhiyun struct task_struct *p = (void *)ctx[0];
54*4882a593Smuzhiyun
55*4882a593Smuzhiyun return trace_enqueue(p->tgid, p->pid);
56*4882a593Smuzhiyun }
57*4882a593Smuzhiyun
58*4882a593Smuzhiyun SEC("tp_btf/sched_switch")
handle__sched_switch(u64 * ctx)59*4882a593Smuzhiyun int handle__sched_switch(u64 *ctx)
60*4882a593Smuzhiyun {
61*4882a593Smuzhiyun /* TP_PROTO(bool preempt, struct task_struct *prev,
62*4882a593Smuzhiyun * struct task_struct *next)
63*4882a593Smuzhiyun */
64*4882a593Smuzhiyun struct task_struct *prev = (struct task_struct *)ctx[1];
65*4882a593Smuzhiyun struct task_struct *next = (struct task_struct *)ctx[2];
66*4882a593Smuzhiyun struct event event = {};
67*4882a593Smuzhiyun u64 *tsp, delta_us;
68*4882a593Smuzhiyun long state;
69*4882a593Smuzhiyun u32 pid;
70*4882a593Smuzhiyun
71*4882a593Smuzhiyun /* ivcsw: treat like an enqueue event and store timestamp */
72*4882a593Smuzhiyun if (prev->state == TASK_RUNNING)
73*4882a593Smuzhiyun trace_enqueue(prev->tgid, prev->pid);
74*4882a593Smuzhiyun
75*4882a593Smuzhiyun pid = next->pid;
76*4882a593Smuzhiyun
77*4882a593Smuzhiyun /* fetch timestamp and calculate delta */
78*4882a593Smuzhiyun tsp = bpf_map_lookup_elem(&start, &pid);
79*4882a593Smuzhiyun if (!tsp)
80*4882a593Smuzhiyun return 0; /* missed enqueue */
81*4882a593Smuzhiyun
82*4882a593Smuzhiyun delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;
83*4882a593Smuzhiyun if (min_us && delta_us <= min_us)
84*4882a593Smuzhiyun return 0;
85*4882a593Smuzhiyun
86*4882a593Smuzhiyun event.pid = pid;
87*4882a593Smuzhiyun event.delta_us = delta_us;
88*4882a593Smuzhiyun bpf_get_current_comm(&event.task, sizeof(event.task));
89*4882a593Smuzhiyun
90*4882a593Smuzhiyun /* output */
91*4882a593Smuzhiyun bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
92*4882a593Smuzhiyun &event, sizeof(event));
93*4882a593Smuzhiyun
94*4882a593Smuzhiyun bpf_map_delete_elem(&start, &pid);
95*4882a593Smuzhiyun return 0;
96*4882a593Smuzhiyun }
97*4882a593Smuzhiyun
98*4882a593Smuzhiyun char LICENSE[] SEC("license") = "GPL";
99