1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2019 Facebook
4 #include <bpf/bpf_helpers.h>
5 #include "runqslower.h"
9 const volatile __u64 min_us = 0;
10 const volatile pid_t targ_pid = 0;
13 __uint(type, BPF_MAP_TYPE_HASH);
14 __uint(max_entries, 10240);
20 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
21 __uint(key_size, sizeof(u32));
22 __uint(value_size, sizeof(u32));
23 } events SEC(".maps");
25 /* record enqueue timestamp */
27 static int trace_enqueue(u32 tgid, u32 pid)
31 if (!pid || (targ_pid && targ_pid != pid))
34 ts = bpf_ktime_get_ns();
35 bpf_map_update_elem(&start, &pid, &ts, 0);
39 SEC("tp_btf/sched_wakeup")
40 int handle__sched_wakeup(u64 *ctx)
42 /* TP_PROTO(struct task_struct *p) */
43 struct task_struct *p = (void *)ctx[0];
45 return trace_enqueue(p->tgid, p->pid);
48 SEC("tp_btf/sched_wakeup_new")
49 int handle__sched_wakeup_new(u64 *ctx)
51 /* TP_PROTO(struct task_struct *p) */
52 struct task_struct *p = (void *)ctx[0];
54 return trace_enqueue(p->tgid, p->pid);
57 SEC("tp_btf/sched_switch")
58 int handle__sched_switch(u64 *ctx)
60 /* TP_PROTO(bool preempt, struct task_struct *prev,
61 * struct task_struct *next)
63 struct task_struct *prev = (struct task_struct *)ctx[1];
64 struct task_struct *next = (struct task_struct *)ctx[2];
65 struct event event = {};
70 /* ivcsw: treat like an enqueue event and store timestamp */
71 if (prev->state == TASK_RUNNING)
72 trace_enqueue(prev->tgid, prev->pid);
76 /* fetch timestamp and calculate delta */
77 tsp = bpf_map_lookup_elem(&start, &pid);
79 return 0; /* missed enqueue */
81 delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;
82 if (min_us && delta_us <= min_us)
86 event.delta_us = delta_us;
87 bpf_get_current_comm(&event.task, sizeof(event.task));
90 bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
91 &event, sizeof(event));
93 bpf_map_delete_elem(&start, &pid);
97 char LICENSE[] SEC("license") = "GPL";