1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2019 Facebook
4 #include <bpf/bpf_helpers.h>
5 #include "runqslower.h"
8 #define BPF_F_CURRENT_CPU 0xffffffffULL
10 const volatile __u64 min_us = 0;
11 const volatile pid_t targ_pid = 0;
14 __uint(type, BPF_MAP_TYPE_HASH);
15 __uint(max_entries, 10240);
21 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
22 __uint(key_size, sizeof(u32));
23 __uint(value_size, sizeof(u32));
24 } events SEC(".maps");
26 /* record enqueue timestamp */
28 static int trace_enqueue(u32 tgid, u32 pid)
32 if (!pid || (targ_pid && targ_pid != pid))
35 ts = bpf_ktime_get_ns();
36 bpf_map_update_elem(&start, &pid, &ts, 0);
40 SEC("tp_btf/sched_wakeup")
41 int handle__sched_wakeup(u64 *ctx)
43 /* TP_PROTO(struct task_struct *p) */
44 struct task_struct *p = (void *)ctx[0];
46 return trace_enqueue(p->tgid, p->pid);
49 SEC("tp_btf/sched_wakeup_new")
50 int handle__sched_wakeup_new(u64 *ctx)
52 /* TP_PROTO(struct task_struct *p) */
53 struct task_struct *p = (void *)ctx[0];
55 return trace_enqueue(p->tgid, p->pid);
58 SEC("tp_btf/sched_switch")
59 int handle__sched_switch(u64 *ctx)
61 /* TP_PROTO(bool preempt, struct task_struct *prev,
62 * struct task_struct *next)
64 struct task_struct *prev = (struct task_struct *)ctx[1];
65 struct task_struct *next = (struct task_struct *)ctx[2];
66 struct event event = {};
71 /* ivcsw: treat like an enqueue event and store timestamp */
72 if (prev->state == TASK_RUNNING)
73 trace_enqueue(prev->tgid, prev->pid);
77 /* fetch timestamp and calculate delta */
78 tsp = bpf_map_lookup_elem(&start, &pid);
80 return 0; /* missed enqueue */
82 delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;
83 if (min_us && delta_us <= min_us)
87 event.delta_us = delta_us;
88 bpf_get_current_comm(&event.task, sizeof(event.task));
91 bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
92 &event, sizeof(event));
94 bpf_map_delete_elem(&start, &pid);
98 char LICENSE[] SEC("license") = "GPL";