libbpf-tools: use raw_tp sched_switch instead of kprobe

Signed-off-by: Wenbo Zhang <[email protected]>

libbpf-tools/cpudist.bpf.c

@@ -62,7 +62,8 @@ static __always_inline void update_hist(struct task_struct *task,
  histp = bpf_map_lookup_elem(&hists, &id);
  if (!histp)
  return;
- BPF_CORE_READ_STR_INTO(&histp->comm, task, comm);
+ bpf_probe_read_kernel_str(&histp->comm, sizeof(task->comm),
+ task->comm);
  }
  delta = ts - *tsp;
  if (targ_ms)
@@ -75,20 +76,19 @@ static __always_inline void update_hist(struct task_struct *task,
  __sync_fetch_and_add(&histp->slots[slot], 1);
 }
 
-SEC("kprobe/finish_task_switch")
-int BPF_KPROBE(finish_task_switch, struct task_struct *prev)
+SEC("tp_btf/sched_switch")
+int BPF_PROG(sched_switch, bool preempt, struct task_struct *prev,
+ struct task_struct *next)
 {
- u32 prev_tgid = BPF_CORE_READ(prev, tgid);
- u32 prev_pid = BPF_CORE_READ(prev, pid);
- u64 id = bpf_get_current_pid_tgid();
- u32 tgid = id >> 32, pid = id;
+ u32 prev_tgid = prev->tgid, prev_pid = prev->pid;
+ u32 tgid = next->tgid, pid = next->pid;
  u64 ts = bpf_ktime_get_ns();
 
  if (targ_offcpu) {
  store_start(prev_tgid, prev_pid, ts);
- update_hist((void*)bpf_get_current_task(), tgid, pid, ts);
+ update_hist(next, tgid, pid, ts);
  } else {
- if (BPF_CORE_READ(prev, state) == TASK_RUNNING)
+ if (prev->state == TASK_RUNNING)
  update_hist(prev, prev_tgid, prev_pid, ts);
  store_start(tgid, pid, ts);
  }