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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 | // SPDX-License-Identifier: GPL-2.0 // Copyright (c) 2019 Facebook #include "vmlinux.h" #include <bpf/bpf_helpers.h> #include "runqslower.h" #define TASK_RUNNING 0 #define BPF_F_CURRENT_CPU 0xffffffffULL const volatile __u64 min_us = 0; const volatile pid_t targ_pid = 0; struct { __uint(type, BPF_MAP_TYPE_TASK_STORAGE); __uint(map_flags, BPF_F_NO_PREALLOC); __type(key, int); __type(value, u64); } start SEC(".maps"); struct { __uint(type, BPF_MAP_TYPE_PERF_EVENT_ARRAY); __uint(key_size, sizeof(u32)); __uint(value_size, sizeof(u32)); } events SEC(".maps"); /* record enqueue timestamp */ __always_inline static int trace_enqueue(struct task_struct *t) { u32 pid = t->pid; u64 *ptr; if (!pid || (targ_pid && targ_pid != pid)) return 0; ptr = bpf_task_storage_get(&start, t, 0, BPF_LOCAL_STORAGE_GET_F_CREATE); if (!ptr) return 0; *ptr = bpf_ktime_get_ns(); return 0; } SEC("tp_btf/sched_wakeup") int handle__sched_wakeup(u64 *ctx) { /* TP_PROTO(struct task_struct *p) */ struct task_struct *p = (void *)ctx[0]; return trace_enqueue(p); } SEC("tp_btf/sched_wakeup_new") int handle__sched_wakeup_new(u64 *ctx) { /* TP_PROTO(struct task_struct *p) */ struct task_struct *p = (void *)ctx[0]; return trace_enqueue(p); } SEC("tp_btf/sched_switch") int handle__sched_switch(u64 *ctx) { /* TP_PROTO(bool preempt, struct task_struct *prev, * struct task_struct *next) */ struct task_struct *prev = (struct task_struct *)ctx[1]; struct task_struct *next = (struct task_struct *)ctx[2]; struct runq_event event = {}; u64 *tsp, delta_us; long state; u32 pid; /* ivcsw: treat like an enqueue event and store timestamp */ if (prev->__state == TASK_RUNNING) trace_enqueue(prev); pid = next->pid; /* For pid mismatch, save a bpf_task_storage_get */ if (!pid || (targ_pid && targ_pid != pid)) return 0; /* fetch timestamp and calculate delta */ tsp = bpf_task_storage_get(&start, next, 0, 0); if (!tsp) return 0; /* missed enqueue */ delta_us = (bpf_ktime_get_ns() - *tsp) / 1000; if (min_us && delta_us <= min_us) return 0; event.pid = pid; event.delta_us = delta_us; bpf_get_current_comm(&event.task, sizeof(event.task)); /* output */ bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU, &event, sizeof(event)); bpf_task_storage_delete(&start, next); return 0; } char LICENSE[] SEC("license") = "GPL"; |