在​​/proc/[pid]/stat​​​里有该进程的详细信息。其内容的解释可以在​​man 5 proc​​​里查看（搜​​/stat​​）

相关部分如下：

(14) utime%lu
          Amount of time that this process has been scheduled in user mode, measured
          in  clock  ticks  (divide  by  sysconf(_SC_CLK_TCK)).  This includes guest
          time, guest_time (time spent running a virtual CPU, see  below),  so  that
          applications  that  are not aware of the guest time field do not lose that
          time from their calculations.

(15) stime  %lu
          Amount of time that this process has been scheduled in kernel  mode,  mea‐
          sured in clock ticks (divide by sysconf(_SC_CLK_TCK)).

(16) cutime  %ld
          Amount of time that this process's waited-for children have been scheduled
          in user mode, measured in clock ticks  (divide  by  sysconf(_SC_CLK_TCK)).
          (See  also  times(2).)   This includes guest time, cguest_time (time spent
          running a virtual CPU, see below).

(17) cstime  %ld
          Amount of time that this process's waited-for children have been scheduled
          in kernel mode, measured in clock ticks (divide by sysconf(_SC_CLK_TCK)).

一个进程里的所有线程的stat文件的内容都是一样的。