编写设备驱动程序

任务队列 DTrace SDT 探测器

任务队列提供了若干个有用的 SDT 探测器。本节介绍的所有探测器都具有以下两个参数:

可以使用这些探测器来收集有关各个任务队列以及通过这些队列执行的各个任务的精确计时信息。例如,以下脚本每隔 10 秒列显通过任务队列调度的函数:


# !/usr/sbin/dtrace -qs

sdt:genunix::taskq-enqueue
{
  this->tq  = (taskq_t *)arg0;
  this->tqe = (taskq_ent_t *) arg1;
  @[this->tq->tq_name,
    this->tq->tq_instance,
    this->tqe->tqent_func] = count();
}

tick-10s
{
  printa ("%s(%d): %a called %@d times\n", @);
  trunc(@);
}

在特定的计算机上,以上 D 脚本生成以下输出:


callout_taskq(1): genunix`callout_execute called 51 times
callout_taskq(0): genunix`callout_execute called 701 times
kmem_taskq(0): genunix`kmem_update_timeout called 1 times
kmem_taskq(0): genunix`kmem_hash_rescale called 4 times
callout_taskq(1): genunix`callout_execute called 40 times
USB_hid_81_pipehndl_tq_1(14): usba`hcdi_cb_thread called 256 times
callout_taskq(0): genunix`callout_execute called 702 times
kmem_taskq(0): genunix`kmem_update_timeout called 1 times
kmem_taskq(0): genunix`kmem_hash_rescale called 4 times
callout_taskq(1): genunix`callout_execute called 28 times
USB_hid_81_pipehndl_tq_1(14): usba`hcdi_cb_thread called 228 times
callout_taskq(0): genunix`callout_execute called 706 times
callout_taskq(1): genunix`callout_execute called 24 times
USB_hid_81_pipehndl_tq_1(14): usba`hcdi_cb_thread called 141 times
callout_taskq(0): genunix`callout_execute called 708 times