1 // SPDX-License-Identifier: GPL-2.0
2 // Copyright (c) 2019 Facebook
4 #include <bpf/bpf_helpers.h>
5 #include "runqslower.h"
9 #define BPF_F_INDEX_MASK 0xffffffffULL
10 #define BPF_F_CURRENT_CPU BPF_F_INDEX_MASK
12 const volatile __u64 min_us = 0;
13 const volatile pid_t targ_pid = 0;
16 __uint(type, BPF_MAP_TYPE_HASH);
17 __uint(max_entries, 10240);
23 __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY);
24 __uint(key_size, sizeof(u32));
25 __uint(value_size, sizeof(u32));
26 } events SEC(".maps");
28 /* record enqueue timestamp */
30 static int trace_enqueue(u32 tgid, u32 pid)
34 if (!pid || (targ_pid && targ_pid != pid))
37 ts = bpf_ktime_get_ns();
38 bpf_map_update_elem(&start, &pid, &ts, 0);
42 SEC("tp_btf/sched_wakeup")
43 int handle__sched_wakeup(u64 *ctx)
45 /* TP_PROTO(struct task_struct *p) */
46 struct task_struct *p = (void *)ctx[0];
48 return trace_enqueue(p->tgid, p->pid);
51 SEC("tp_btf/sched_wakeup_new")
52 int handle__sched_wakeup_new(u64 *ctx)
54 /* TP_PROTO(struct task_struct *p) */
55 struct task_struct *p = (void *)ctx[0];
57 return trace_enqueue(p->tgid, p->pid);
60 SEC("tp_btf/sched_switch")
61 int handle__sched_switch(u64 *ctx)
63 /* TP_PROTO(bool preempt, struct task_struct *prev,
64 * struct task_struct *next)
66 struct task_struct *prev = (struct task_struct *)ctx[1];
67 struct task_struct *next = (struct task_struct *)ctx[2];
68 struct event event = {};
73 /* ivcsw: treat like an enqueue event and store timestamp */
74 if (prev->state == TASK_RUNNING)
75 trace_enqueue(prev->tgid, prev->pid);
79 /* fetch timestamp and calculate delta */
80 tsp = bpf_map_lookup_elem(&start, &pid);
82 return 0; /* missed enqueue */
84 delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;
85 if (min_us && delta_us <= min_us)
89 event.delta_us = delta_us;
90 bpf_get_current_comm(&event.task, sizeof(event.task));
93 bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,
94 &event, sizeof(event));
96 bpf_map_delete_elem(&start, &pid);
100 char LICENSE[] SEC("license") = "GPL";