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1// SPDX-License-Identifier: GPL-2.02// Copyright (c) 2019 Facebook3#include "vmlinux.h"4#include <bpf/bpf_helpers.h>5#include "runqslower.h"6 7#define TASK_RUNNING 08#define BPF_F_CURRENT_CPU 0xffffffffULL9 10const volatile __u64 min_us = 0;11const volatile pid_t targ_pid = 0;12 13struct {14 __uint(type, BPF_MAP_TYPE_TASK_STORAGE);15 __uint(map_flags, BPF_F_NO_PREALLOC);16 __type(key, int);17 __type(value, u64);18} start SEC(".maps");19 20struct {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");25 26/* record enqueue timestamp */27__always_inline28static int trace_enqueue(struct task_struct *t)29{30 u32 pid = t->pid;31 u64 *ptr;32 33 if (!pid || (targ_pid && targ_pid != pid))34 return 0;35 36 ptr = bpf_task_storage_get(&start, t, 0,37 BPF_LOCAL_STORAGE_GET_F_CREATE);38 if (!ptr)39 return 0;40 41 *ptr = bpf_ktime_get_ns();42 return 0;43}44 45SEC("tp_btf/sched_wakeup")46int handle__sched_wakeup(u64 *ctx)47{48 /* TP_PROTO(struct task_struct *p) */49 struct task_struct *p = (void *)ctx[0];50 51 return trace_enqueue(p);52}53 54SEC("tp_btf/sched_wakeup_new")55int handle__sched_wakeup_new(u64 *ctx)56{57 /* TP_PROTO(struct task_struct *p) */58 struct task_struct *p = (void *)ctx[0];59 60 return trace_enqueue(p);61}62 63SEC("tp_btf/sched_switch")64int handle__sched_switch(u64 *ctx)65{66 /* TP_PROTO(bool preempt, struct task_struct *prev,67 * struct task_struct *next)68 */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 = {};72 u64 *tsp, delta_us;73 long state;74 u32 pid;75 76 /* ivcsw: treat like an enqueue event and store timestamp */77 if (prev->__state == TASK_RUNNING)78 trace_enqueue(prev);79 80 pid = next->pid;81 82 /* For pid mismatch, save a bpf_task_storage_get */83 if (!pid || (targ_pid && targ_pid != pid))84 return 0;85 86 /* fetch timestamp and calculate delta */87 tsp = bpf_task_storage_get(&start, next, 0, 0);88 if (!tsp)89 return 0; /* missed enqueue */90 91 delta_us = (bpf_ktime_get_ns() - *tsp) / 1000;92 if (min_us && delta_us <= min_us)93 return 0;94 95 event.pid = pid;96 event.delta_us = delta_us;97 bpf_get_current_comm(&event.task, sizeof(event.task));98 99 /* output */100 bpf_perf_event_output(ctx, &events, BPF_F_CURRENT_CPU,101 &event, sizeof(event));102 103 bpf_task_storage_delete(&start, next);104 return 0;105}106 107char LICENSE[] SEC("license") = "GPL";108