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_TASK_STORAGE);
15 __uint(map_flags, BPF_F_NO_PREALLOC);
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(struct task_struct *t)
33 if (!pid || (targ_pid && targ_pid != pid))
36 ptr = bpf_task_storage_get(&start, t, 0,
37 BPF_LOCAL_STORAGE_GET_F_CREATE);
41 *ptr = bpf_ktime_get_ns();
45 SEC("tp_btf/sched_wakeup")
46 int handle__sched_wakeup(u64 *ctx)
48 /* TP_PROTO(struct task_struct *p) */
49 struct task_struct *p = (void *)ctx[0];
51 return trace_enqueue(p);
54 SEC("tp_btf/sched_wakeup_new")
55 int handle__sched_wakeup_new(u64 *ctx)
57 /* TP_PROTO(struct task_struct *p) */
58 struct task_struct *p = (void *)ctx[0];
60 return trace_enqueue(p);
63 SEC("tp_btf/sched_switch")
64 int handle__sched_switch(u64 *ctx)
66 /* TP_PROTO(bool preempt, struct task_struct *prev,
67 * struct task_struct *next)
69 struct task_struct *prev = (struct task_struct *)ctx[1];
70 struct task_struct *next = (struct task_struct *)ctx[2];
71 struct runq_event event = {};
76 /* ivcsw: treat like an enqueue event and store timestamp */
77 if (prev->__state == TASK_RUNNING)
82 /* For pid mismatch, save a bpf_task_storage_get */
83 if (!pid || (targ_pid && targ_pid != pid))
86 /* fetch timestamp and calculate delta */
87 tsp = bpf_task_storage_get(&start, next, 0, 0);
89 return 0; /* missed enqueue */
91 delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;
92 if (min_us && delta_us <= min_us)
96 event.delta_us = delta_us;
97 bpf_get_current_comm(&event.task, sizeof(event.task));
100 bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
101 &event, sizeof(event));
103 bpf_task_storage_delete(&start, next);
107 char LICENSE[] SEC("license") = "GPL";